avformat/demux: use correct close function for custom io

You may look and think `AVFMT_FLAG_CUSTOM_IO` check is enough, but this
is not what it seems. This flag means that user provided custom
AVIOContext, before creating AVFormatContext and it should not be
closed. However nested sub-demuxers may still open an temporary io, and
those have to be closed and use correct io_close2 function.

You can see 0dcac9c3f0 and
ef01061225 where this flag is cleared for
nested opens to avoid leaking those.

lavf micro version bumped so API users can know if it is safe to use
custom io.

Signed-off-by: Kacper Michajłow <kasper93@gmail.com>

libavformat/demux.c

@@ -368,7 +368,7 @@ fail:
     ff_id3v2_free_extra_meta(&id3v2_extra_meta);
     av_dict_free(&tmp);
     if (s->pb && !(s->flags & AVFMT_FLAG_CUSTOM_IO))
-        avio_closep(&s->pb);
+        ff_format_io_close(s, &s->pb);
     avformat_free_context(s);
     *ps = NULL;
     return ret;

libavformat/version.h

@@ -32,7 +32,7 @@
 #include "version_major.h"
 
 #define LIBAVFORMAT_VERSION_MINOR  15
-#define LIBAVFORMAT_VERSION_MICRO 100
+#define LIBAVFORMAT_VERSION_MICRO 101
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \