avcodec: Remove fallback definitions of AVDictionaryEntry and av_dict_get

These fallback definitions (since they were moved to avcommon_compat.h
in 5e192e1e) caused the avcodec plugin to use av_metadata_get for uses
of av_dict_get, while av_metadata_get is defined in libavformat (which
the avcodec plugin doesn't link to).

Both AVDictionaryEntry and av_dict_get were added in libavutil
51.5.0, which is earlier than the minimum required version of libavutil
that vlc requires (51.22.0).

This fixes using the avcodec plugin in builds with libavformat < 54
(such as on debian wheezy).

This is not cherry-picked from vlc.git, since the master branch there
has dropped support for such old libavformat versions altogether.
Signed-off-by: Martin Storsjö <martin@martin.st>

modules/codec/avcodec/avcommon_compat.h

@@ -513,11 +513,6 @@ enum {
     ( (LIBAVFORMAT_VERSION_MICRO <  100 && LIBAVFORMAT_VERSION_INT >= AV_VERSION_INT( a, b, c ) ) || \
       (LIBAVFORMAT_VERSION_MICRO >= 100 && LIBAVFORMAT_VERSION_INT >= AV_VERSION_INT( a, d, e ) ) )
 
-#if LIBAVFORMAT_VERSION_MAJOR < 54
-# define AVDictionaryEntry AVMetadataTag
-# define av_dict_get av_metadata_get
-#endif
-
 #endif
 
 #endif