Enable proper display of elapsed time when paused with VAAPI.

Make sure av_pause_frame is updated so that the player can pick up the
current frame number while paused.  Refs #10962
(cherry picked from commit 841ff3a359ce668eb51ef1da917ffab5a0932302)

Conflicts:

	mythtv/libs/libmythtv/videoout_openglvaapi.cpp
(cherry picked from commit 6be8c10b39dcbe0fe825d22fec70795d87972a25)