pvr: fix duplicate EPG IDs if EPG is not stored in database
ff_id3v2_free_extra_meta: set the pointer pointing to extra_meta to NULL

Fixes ticket #3530.

Signed-off-by: Peter Ross <pross@xvid.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
FFmpeg: Cherry-pick c94305ae23318c8956a30485cd5642829f4f16a9 to fix #15085
Merge pull request #4583 from fritsch/xbmc-upstream

ffmpeg: Backport c94305ae23318c8956a30485cd5642829f4f16a9 to fix #15085
Merge pull request #4581 from FernetMenta/epg

pvr: fix duplicate EPG IDs if EPG is not stored in database
[coreSubs] focus subtitle list if subs are found
[coreSubs] allow search on same service
Merge pull request #4591 from amet/subs_fixes

Subs search fixes
[depends] move ffmpeg to unified deps
[configure] remove internal ffmpeg
ffmpeg: remove dll wrappers
add ffmpeg lock manager
todo: refactor to own file
ffmpeg: move callbacks into separate file
remove ffmpeg dlls from generated headers
not removing win32 as this might still be needed?
[rpi] setup-sdk.sh: allow overriding of buildroot and xbmc install paths
also don't require root if not needed
add ffmpeg makefile for rpi
[WIN32] download and compile ffmpeg from remote source.
[WIN32] make XBMC compile, build and run with the ffmpeg link libraries.
[WIN32] use ffmpeg version from tools\depends\target\ffmpeg\FFMPEG-VERSION
[WIN32] prepare mingw build files for jenkins.