add drawValidate when calling glCheckFramebufferStatus
in the draw validate, a color attachement will be added to the
framebuffer if there is no target attached to COLOR_ATTACHMENT
of the framebuffer.
opengl does not allow framebuffer with no color attachement
so CheckFramebufferStatus would return INCOMPLETE status.
We already call drawValidate before any draw, the call was
missing at glCheckFramebufferStatus.
Change-Id: I94b930024c3076ac5fe0f8662d11884729c4f953
f7e7e467ce