ipaccess: don't close the signalling link if we receive bad OML/RSL message

Instead, propagate the error to upper layers. This fixes a segfault
in the BSC if bad OML/RSL message is received.
diff --git a/src/input/ipaccess.c b/src/input/ipaccess.c
index 836c2f8..8871246 100644
--- a/src/input/ipaccess.c
+++ b/src/input/ipaccess.c
@@ -424,7 +424,6 @@
 		LOGP(DLINP, LOGL_ERROR, "Bad signalling message,"
 				       "closing socket.\n");
 		ret = -EINVAL;
-		goto err;
 	}
 	return ret;
 err: