Restore the optimization to skip revalidation in selinux_file_permission
if nothing has changed since the dentry_open checks, accidentally removed by
389fb800.  Also remove redundant test from selinux_revalidate_file_permission.
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Reviewed-by: NPaul Moore <paul.moore@hp.com>
Acked-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NJames Morris <jmorris@namei.org>