vc1testenc: give muxer same name as demuxer

Otherwise ffmpeg -formats claims that we only support demuxing
of that format.
To keep compatibility the struct could be duplicated instead,
but this seems almost like overkill for such a rare format.
Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>

libavformat/vc1testenc.c

@@ -83,7 +83,7 @@ static int vc1test_write_trailer(AVFormatContext *s)
 }
 
 AVOutputFormat ff_vc1t_muxer = {
-    .name              = "rcv",
+    .name              = "vc1test",
     .long_name         = NULL_IF_CONFIG_SMALL("VC-1 test bitstream"),
     .extensions        = "rcv",
     .priv_data_size    = sizeof(RCVContext),