[nat] Make create_sccp_src_ref return the SCCP Connection.

Right now it was not possible to just find a connection, by returning
the connection that is created we will have direct access to it. It
will be used by the local connection handling.
diff --git a/openbsc/tests/bsc-nat/bsc_nat_test.c b/openbsc/tests/bsc-nat/bsc_nat_test.c
index ca9fbd4..6ad9870 100644
--- a/openbsc/tests/bsc-nat/bsc_nat_test.c
+++ b/openbsc/tests/bsc-nat/bsc_nat_test.c
@@ -273,10 +273,10 @@
 /* test conn tracking once */
 static void test_contrack()
 {
-	int rc;
 	struct bsc_nat *nat;
 	struct bsc_connection *con;
 	struct sccp_connections *con_found;
+	struct sccp_connections *rc_con;
 	struct bsc_nat_parsed *parsed;
 	struct msgb *msg;
 
@@ -294,8 +294,8 @@
 		fprintf(stderr, "Con should not exist %p\n", con_found);
 		abort();
 	}
-	rc = create_sccp_src_ref(con, parsed);
-	if (rc != 0) {
+	rc_con = create_sccp_src_ref(con, parsed);
+	if (!rc_con) {
 		fprintf(stderr, "Failed to create a ref\n");
 		abort();
 	}
@@ -304,6 +304,10 @@
 		fprintf(stderr, "Failed to find the con: %p\n", con_found);
 		abort();
 	}
+	if (con_found != rc_con) {
+		fprintf(stderr, "Failed to find the right connection.\n");
+		abort();
+	}
 	if (memcmp(msg->data, bsc_cr_patched, sizeof(bsc_cr_patched)) != 0) {
 		fprintf(stderr, "Failed to patch the BSC CR msg.\n");
 		abort();