d3451f7f9c
From the ARB_ES2_compatibility spec:
"(8) How should we handle draw buffer completeness?
RESOLVED: Remove draw/readbuffer completeness checks, and treat
drawbuffers referring to missing attachments as if they were NONE."
Fixes arb_es2_compatibility-drawbuffers when the short-circuit for
ARB_ES2_compatibility in the previous commit is dropped.
Reviewed-by: Brian Paul <brianp@vmware.com>