cgms are image/cgm

bin/get-bugzilla-attachments-by-mimetype

@@ -237,6 +237,7 @@ image_mimetypes = [
     ('image/gif', 'gif'),
     ('image/jpeg', 'jpeg'),
     ('image/png', 'png'),
+    ('image/cgm', 'cgm'),
 ]
 
 for (mimetype,extension) in mimetypes:

filter/source/config/fragments/types/impress_CGM_Computer_Graphics_Metafile.xcu

@@ -2,7 +2,7 @@
         <prop oor:name="DetectService"><value>com.sun.star.comp.draw.FormatDetector</value></prop>
         <prop oor:name="URLPattern"/>
         <prop oor:name="Extensions"><value>cgm</value></prop>
-        <prop oor:name="MediaType"/>
+        <prop oor:name="MediaType"><value>image/cgm</value></prop>
         <prop oor:name="Preferred"><value>false</value></prop>
         <prop oor:name="PreferredFilter"><value>CGM - Computer Graphics Metafile</value></prop>
         <prop oor:name="UIName">