Make QuickSyncEncoder get its textures from ResourcePool.

Make QuickSyncEncoder get its textures from ResourcePool.

This fixes a problem where the ResourcePool would not be aware
that a given texture had been deleted (and a new one come back
using the same texture number), and thus happily continue
to give out cached FBOs from it, even though OpenGL had unlinked
those FBOs when the texture was deleted.