Change SVN to Git in configure

Changes "version from SVN" to "version from Git".

Signed-off-by: Janne Grunau <janne-ffmpeg@jannau.net>

configure

@@ -277,7 +277,7 @@ die(){
     cat <<EOF
 
 If you think configure made a mistake, make sure you are using the latest
-version from SVN.  If the latest version fails, report the problem to the
+version from Git.  If the latest version fails, report the problem to the
 ffmpeg-user@mplayerhq.hu mailing list or IRC #ffmpeg on irc.freenode.net.
 EOF
     if disabled logging; then