Fix check when loading persistence file of a different version

Closes #1684. Thanks to grekhss.

ChangeLog.txt

@@ -8,6 +8,8 @@ Broker:
 - Don't disconnect clients that are already disconnected. This prevents the
   session expiry being extended on SIGHUP. Closes #1521.
 - Fix support for openssl 3.0.
+- Fix check when loading persistence file of a different version than the
+  native version. Closes #1684.
  
 Client library:
 - Don't treat an unexpected PUBACK, PUBREL, or PUBCOMP as a fatal error.

src/persist_read.c

@@ -415,7 +415,7 @@ int persist__restore(struct mosquitto_db *db)
 		/* IMPORTANT - this is where compatibility checks are made.
 		 * Is your DB change still compatible with previous versions?
 		 */
-		if(db_version > MOSQ_DB_VERSION && db_version != 0){
+		if(db_version != MOSQ_DB_VERSION){
 			if(db_version == 4){
 			}else if(db_version == 3){
 				/* Addition of source_username and source_port to msg_store chunk in v4, v1.5.6 */