🐛 Use OldHostname when querying the Database

In BaseRule.baseUpdate our goal is to check if a hostname exists before
trying to rename that hostname into something else. This patch fixes an
error where the newly generated Hostname was used to check for the
existence of the old hostname.

rules/interface.go

@@ -32,7 +32,7 @@ func (br *BaseRule) baseInsert(category string, hostname string, paramsJSON []by
 }
 
 func (br *BaseRule) baseUpdate(category string, oldhostname string, hostname string, paramsJSON []byte) error {
-	exists, err := db.HostnameExists(category, hostname)
+	exists, err := db.HostnameExists(category, oldhostname)
 	if err != nil {
 		return fmt.Errorf("error checking existence of hostname: %v", err.Error())
 	}