Associate .tga with format image2.

Originally committed as revision 24079 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/img2.c

@@ -442,7 +442,7 @@ AVOutputFormat image2_muxer = {
     "image2",
     NULL_IF_CONFIG_SMALL("image2 sequence"),
     "",
-    "bmp,jpeg,jpg,ljpg,pam,pbm,pcx,pgm,pgmyuv,png,ppm,sgi,tif,tiff,jp2",
+    "bmp,jpeg,jpg,ljpg,pam,pbm,pcx,pgm,pgmyuv,png,ppm,sgi,tga,tif,tiff,jp2",
     sizeof(VideoData),
     CODEC_ID_NONE,
     CODEC_ID_MJPEG,