apparmor: fix mediation of prlimit

For primit apparmor requires that if target confinement does not match
the setting task's confinement, the setting task requires CAP_SYS_RESOURCE.

Unfortunately this was broken when rlimit enforcement was reworked to
support labels.

Fixes: 86b92cb7 ("apparmor: move resource checks to using labels")
Signed-off-by: John Johansen <john.johansen@canonical.com>

security/apparmor/resource.c

@@ -124,7 +124,7 @@ int aa_task_setrlimit(struct aa_label *label, struct task_struct *task,
 	 */
 
 	if (label != peer &&
-	    !aa_capable(label, CAP_SYS_RESOURCE, SECURITY_CAP_NOAUDIT))
+	    aa_capable(label, CAP_SYS_RESOURCE, SECURITY_CAP_NOAUDIT) != 0)
 		error = fn_for_each(label, profile,
 				audit_resource(profile, resource,
 					       new_rlim->rlim_max, peer,