audit: refactor audit_receive_msg() to clarify AUDIT_*_RULE* cases

audit_receive_msg() needlessly contained a fallthrough case that called
audit_receive_filter(), containing no common code between the cases.  Separate
them to make the logic clearer.  Refactor AUDIT_LIST_RULES, AUDIT_ADD_RULE,
AUDIT_DEL_RULE cases to create audit_rule_change(), audit_list_rules_send()
functions.  This should not functionally change the logic.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/kernel/audit.c b/kernel/audit.c
index fdb8528..c460f33 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -903,11 +903,12 @@
 			audit_log_end(ab);
 			return -EPERM;
 		}
-		/* fallthrough */
-	case AUDIT_LIST_RULES:
-		err = audit_receive_filter(msg_type, NETLINK_CB(skb).portid,
+		err = audit_rule_change(msg_type, NETLINK_CB(skb).portid,
 					   seq, data, nlmsg_len(nlh));
 		break;
+	case AUDIT_LIST_RULES:
+		err = audit_list_rules_send(NETLINK_CB(skb).portid, seq);
+		break;
 	case AUDIT_TRIM:
 		audit_trim_trees();
 		audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);