modules/compose: don't clear frame in prepare_frame()

I'm not sure why this was being done, it was probably just
vestigial from whatever I bootstrapped the compose module with
and never thought to remove it.

The first compose layer rendered will clear the frame if
necessary.  By compose doing it ahead of time, it's performing
potentially unnecessary work clearing if the first layer is a
frame-filler style render where no clear is ever performed.

0 files changed, 0 insertions, 0 deletions