Add test if flush fails

htdocs/lib/databases/mysql.lib.php

@@ -1005,6 +1005,7 @@ class DoliDb
 		$resql=$this->query($sql);
 		if (! $resql)
 		{
+			dol_syslog("mysqli.lib::DDLCreateUser sql=".$sql, LOG_ERR);
 			return -1;
 		}
 
@@ -1017,6 +1018,7 @@ class DoliDb
 		$resql=$this->query($sql);
 		if (! $resql)
 		{
+			dol_syslog("mysqli.lib::DDLCreateUser sql=".$sql, LOG_ERR);
 			return -1;
 		}
 
@@ -1026,6 +1028,7 @@ class DoliDb
 		$resql=$this->query($sql);
 		if (! $resql)
 		{
+			dol_syslog("mysqli.lib::DDLCreateUser sql=".$sql, LOG_ERR);
 			return -1;
 		}