Before this patch, each individual "go_lock" glock operation (glop)
checked the GL_SKIP flag, and if set, would skip further processing.

This patch changes the logic so the go_lock caller, function go_promote,
checks the GL_SKIP flag before calling the go_lock op in the first place.
This avoids having to unnecessarily unlock gl_lockref.lock only to
re-lock it again.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>