pipeline: don't skip flush if skip_gl_color flag differs

pipeline: don't skip flush if skip_gl_color flag differs

We try and bail out of flushing pipeline state asap if we can see the
pipeline has already been flushed and hasn't changed but we weren't
checking to see if the skip_gl_color flag is the same as when it was
last flush too and so we'd sometimes bail out without updating the
glColor correctly.