Correct truncated ID3v1 genre name.

Originally committed as revision 20843 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/id3v1.c

@@ -164,7 +164,7 @@ const char * const ff_id3v1_genre_str[ID3v1_GENRE_MAX + 1] = {
     [137] = "Heavy Metal",
     [138] = "Black Metal",
     [139] = "Crossover",
-    [140] = "Contemporary C",
+    [140] = "Contemporary Christian",
     [141] = "Christian Rock",
     [142] = "Merengue",
     [143] = "Salsa",