Work around vo gl/libass subtitle timing problem

Work around vo gl/libass subtitle timing problem

vo gl generates bitmaps for EOSD content (libass subtitles) when
DRAW_EOSD is called but actual drawing of both EOSD and OSD is done in
draw_osd(). Since draw_osd() was called first it drew the EOSD content
from the previous frame, so the subtitles were always one frame late.
As a simple workaround update EOSD content first, then normal OSD.
This makes vo gl work correctly and should have no effect on anything
else.