ike: Don't rekey IKE_SA while reauthenticating

If we are using make-before-break reauthentication, this could lead to
duplicates as the new IKE_SA wouldn't be able to delete the previous
one if it was replaced by a rekeying.

src/libcharon/sa/ike_sa.c

@@ -1928,7 +1928,8 @@ METHOD(ike_sa_t, delete_, status_t,
 METHOD(ike_sa_t, rekey, status_t,
 	private_ike_sa_t *this)
 {
-	if (this->state == IKE_PASSIVE)
+	if (this->state == IKE_PASSIVE ||
+		has_condition(this, COND_REAUTHENTICATING))
 	{
 		return INVALID_STATE;
 	}