Call x264 and Xvid libx264 and libxvid in the configure output for consistency.

Originally committed as revision 13466 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -1963,8 +1963,8 @@ echo "libnut enabled            ${libnut-no}"
 echo "libschroedinger enabled   ${libschroedinger-no}"
 echo "libtheora enabled         ${libtheora-no}"
 echo "libvorbis enabled         ${libvorbis-no}"
-echo "x264 enabled              ${libx264-no}"
-echo "Xvid enabled              ${libxvid-no}"
+echo "libx264 enabled           ${libx264-no}"
+echo "libxvid enabled           ${libxvid-no}"
 echo "zlib enabled              ${zlib-no}"
 echo "bzlib enabled             ${bzlib-no}"
 echo