update the appstream files to most recent version of the spec

Change-Id: I6b23be2af3ab28431266075da389b62372508961

sysui/desktop/appstream-appdata/libreoffice-base.appdata.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <component type="desktop">
 <id>libreoffice-base.desktop</id>
+<metadata_license>CC0-1.0</metadata_license>
 <project_license>MPL-2.0</project_license>
 <name>LibreOffice Base</name>
-<summary>database manaager part of the LibreOffice productivity suite</summary>
+<summary>Database manaager part of the LibreOffice productivity suite</summary>
 <description>
 <p>
 Base is a powerful database manager, part of the LibreOffice productivity suite.
@@ -29,7 +30,6 @@ to connect to virtually any other existing database engine as well.
 <screenshot type="default">http://www.libreoffice.org/assets/Uploads/Screenshots/Base/Screenshot-78.png</screenshot>
 <screenshot>http://www.libreoffice.org/assets/Uploads/Screenshots/Base/Screenshot-80.png</screenshot>
 </screenshots>
-<project_group>The Document Foundation</project_group>
 <developer_name>The Document Foundation</developer_name>
 <updatecontact>libreoffice_at_lists.freedesktop.org</updatecontact>
 </component>

sysui/desktop/appstream-appdata/libreoffice-calc.appdata.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <component type="desktop">
 <id>libreoffice-calc.desktop</id>
+<metadata_license>CC0-1.0</metadata_license>
 <project_license>MPL-2.0</project_license>
 <name>LibreOffice Calc</name>
-<summary>spreadsheet program of the LibreOffice productivity suite</summary>
+<summary>Spreadsheet program of the LibreOffice productivity suite</summary>
 <description>
 <p>
 Calc is a powerful and extensible spreadsheet program, part of the LibreOffice
@@ -22,7 +23,6 @@ worrying about compatibility.
 <screenshots>
 <screenshot type="default">http://www.libreoffice.org/assets/Uploads/Discover/Screenshots/_resampled/ResizedImage400300-Calc-02-exemple-ods.png</screenshot>
 </screenshots>
-<project_group>The Document Foundation</project_group>
 <developer_name>The Document Foundation</developer_name>
 <updatecontact>libreoffice_at_lists.freedesktop.org</updatecontact>
 </component>

sysui/desktop/appstream-appdata/libreoffice-draw.appdata.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <component type="desktop">
 <id>libreoffice-draw.desktop</id>
+<metadata_license>CC0-1.0</metadata_license>
 <project_license>MPL-2.0</project_license>
 <name>LibreOffice Draw</name>
-<summary>graphics editor part of the LibreOffice productivity suite</summary>
+<summary>Graphics editor part of the LibreOffice productivity suite</summary>
 <description>
 <p>
 LibreOffice Draw is an easy-to-use graphics editor, which empowers you to create
@@ -28,7 +29,6 @@ worrying about compatibility.
 <screenshot type="default">http://www.libreoffice.org/assets/Uploads/Discover/Screenshots/_resampled/ResizedImage400300-Draw-02-Tiger-fdo82219.png</screenshot>
 <screenshot>http://www.libreoffice.org/assets/Uploads/Discover/Screenshots/_resampled/ResizedImage400300-Draw-03-Square-fdo75097.png</screenshot>
 </screenshots>
-<project_group>The Document Foundation</project_group>
 <developer_name>The Document Foundation</developer_name>
 <updatecontact>libreoffice_at_lists.freedesktop.org</updatecontact>
 </component>

sysui/desktop/appstream-appdata/libreoffice-impress.appdata.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <component type="desktop">
 <id>libreoffice-impress.desktop</id>
+<metadata_license>CC0-1.0</metadata_license>
 <project_license>MPL-2.0</project_license>
 <name>LibreOffice Impress</name>
-<summary>presentation program of the LibreOffice productivity suite</summary>
+<summary>Presentation program of the LibreOffice productivity suite</summary>
 <description>
 <p>
 Impress is a presentation program and part of the LibreOffice productivity suite.
@@ -23,7 +24,6 @@ worrying about compatibility.
 <screenshots>
 <screenshot type="default">http://www.libreoffice.org/assets/Uploads/Discover/Screenshots/_resampled/ResizedImage400300-Impress-01-Blank.png</screenshot>
 </screenshots>
-<project_group>The Document Foundation</project_group>
 <developer_name>The Document Foundation</developer_name>
 <updatecontact>libreoffice_at_lists.freedesktop.org</updatecontact>
 </component>

sysui/desktop/appstream-appdata/libreoffice-writer.appdata.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <component type="desktop">
 <id>libreoffice-writer.desktop</id>
+<metadata_license>CC0-1.0</metadata_license>
 <project_license>MPL-2.0</project_license>
 <name>LibreOffice Writer</name>
-<summary>word processor part of the LibreOffice productivity suite</summary>
+<summary>Word processor part of the LibreOffice productivity suite</summary>
 <description>
 <p>
 Writer is the word processor inside LibreOffice productivity suite.
@@ -30,7 +31,6 @@ worrying about compatibility.
 <screenshot type="default">http://www.libreoffice.org/assets/Uploads/Discover/Screenshots/_resampled/ResizedImage400300-Writer-02-Table-of-Contents-Getting-Started-Guide-4-2.png</screenshot>
 <screenshot>http://www.libreoffice.org/assets/Uploads/Discover/Screenshots/_resampled/ResizedImage400300-Writer-03-Technical-Doc-fdo83524.png</screenshot>
 </screenshots>
-<project_group>The Document Foundation</project_group>
 <developer_name>The Document Foundation</developer_name>
 <updatecontact>libreoffice_at_lists.freedesktop.org</updatecontact>
 </component>