avformat/mov: Fix memleaks upon read_header failure

avformat/mov: Fix memleaks upon read_header failure

By default, a demuxer's read_close function is not called automatically
if an error happens when reading the header; instead it is up to the
demuxer to clean up after itself in this case. The mov demuxer did this
by calling its read_close function when it encountered some errors when
reading the header. Yet for other errors (mostly adding side-data to
streams) this has been forgotten, so that all the internal structures
of the demuxer leak.

This commit fixes this by making sure mov_read_close is called when
necessary.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>