Remove docs for the not anymore existing option -convert_tags.

Originally committed as revision 25506 to svn://svn.ffmpeg.org/ffmpeg/trunk

doc/ffprobe-doc.texi

@@ -64,9 +64,6 @@ are prefixed by the string "TAG:".
 
 @table @option
 
-@item -convert_tags
-Convert the tag names in the format container to the generic FFmpeg tag names.
-
 @item -f @var{format}
 Force format to use.