update upstream link

Change-Id: I1ef0e9079c7af6eddae3e3dae11ca8c3899fd59e

external/libexttextcat/README

@@ -3,4 +3,4 @@ N-Gram-Based Text Categorization library
 This guesses the language that input text is written in. Fundamentally
 an adaption of wiseguys libtextcat extended to be UTF-8 aware.
 
-It is hosted at: [http://cgit.freedesktop.org/libreoffice/libexttextcat/]
+It is hosted at: [https://wiki.documentfoundation.org/Libexttextcat]

external/libvisio/README

 Libvisio is library providing ability to interpret and import visio diagrams into various applications.
 
 See also:
-[http://www.freedesktop.org/wiki/Software/libvisio]
+[https://wiki.documentfoundation.org/DLP/Libraries/libvisio]