selinux: check ss_initialized before revalidating an inode label

There is no point in trying to revalidate an inode's security label if
the security server is not yet initialized.
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/selinux/hooks.c

@@ -259,7 +259,7 @@ static int __inode_security_revalidate(struct inode *inode,
 
 	might_sleep_if(may_sleep);
 
-	if (isec->initialized != LABEL_INITIALIZED) {
+	if (ss_initialized && isec->initialized != LABEL_INITIALIZED) {
 		if (!may_sleep)
 			return -ECHILD;