transaction.c: cosmetic: use 'default' branch in trans_free()

Change-Id: Ia28ba52b0ea4771843a2a1faa346f7357604b8aa
diff --git a/src/libmsc/transaction.c b/src/libmsc/transaction.c
index 17f8e96..70a39e8 100644
--- a/src/libmsc/transaction.c
+++ b/src/libmsc/transaction.c
@@ -138,7 +138,7 @@
  */
 void trans_free(struct gsm_trans *trans)
 {
-	enum ran_conn_use conn_usage_token = RAN_CONN_USE_UNTRACKED;
+	enum ran_conn_use conn_usage_token;
 	struct ran_conn *conn;
 
 	switch (trans->protocol) {
@@ -154,6 +154,9 @@
 		_gsm911_nc_ss_trans_free(trans);
 		conn_usage_token = RAN_CONN_USE_TRANS_NC_SS;
 		break;
+	default:
+		conn_usage_token = RAN_CONN_USE_UNTRACKED;
+		break;
 	}
 
 	if (trans->paging_request) {