usrloc: connect to db for main process in PROC_POSTCHILDINIT child init

(cherry picked from commit 4780d46976a7a392f23af0d89f05855d473bcb30)

src/modules/usrloc/usrloc_mod.c

@@ -358,6 +358,16 @@ static int mod_init(void)
 	}
 
 	/* Shall we use database ? */
+	switch (ul_db_mode) {
+		case DB_ONLY:
+		case WRITE_THROUGH:
+		case WRITE_BACK:
+		/*
+		 * register the need to be called post-fork of all children
+		 * with the special rank PROC_POSTCHILDINIT
+		 */
+		ksr_module_set_flag(KSRMOD_FLAG_POSTCHILDINIT);
+	}
 	if (ul_db_mode != NO_DB) { /* Yes */
 		if (db_bind_mod(&ul_db_url, &ul_dbf) < 0) { /* Find database module */
 			LM_ERR("failed to bind database module\n");
@@ -452,14 +462,14 @@ static int child_init(int _rank)
 		case WRITE_THROUGH:
 			/* connect to db only from SIP workers, TIMER and MAIN processes,
 			 *  and RPC processes */
-			if (_rank<=0 && _rank!=PROC_TIMER && _rank!=PROC_MAIN
+			if (_rank<=0 && _rank!=PROC_TIMER && _rank!=PROC_POSTCHILDINIT
 					 && _rank!=PROC_RPC)
 				return 0;
 			break;
 		case WRITE_BACK:
 			/* connect to db only from TIMER (for flush), from MAIN (for
 			 * final flush() and from child 1 for preload */
-			if (_rank!=PROC_TIMER && _rank!=PROC_MAIN && _rank!=PROC_SIPINIT)
+			if (_rank!=PROC_TIMER && _rank!=PROC_POSTCHILDINIT && _rank!=PROC_SIPINIT)
 				return 0;
 			break;
 		case DB_READONLY: