Merge commit 'e1b66778'

* commit 'e1b66778':
  lavc: remove the locking code in avcodec_close()

Conflicts:
	libavcodec/utils.c

Note, if someone knows of a external codec lib/API, hwaccel or other that requires
locking on its close/free side, please contact ffmpeg-devel.

Merged-by: Michael Niedermayer <michaelni@gmx.at>