Some SQL fixes for MariaDB compatibility.

install/sql/ispconfig3.sql

@@ -169,7 +169,7 @@ CREATE TABLE `client` (
   `bank_account_swift` varchar(255) DEFAULT NULL,
   `paypal_email` varchar(255) DEFAULT NULL,
   `default_mailserver` int(11) unsigned NOT NULL DEFAULT '1',
-  `mail_servers` blob NOT NULL DEFAULT '',
+  `mail_servers` blob NOT NULL,
   `limit_maildomain` int(11) NOT NULL DEFAULT '-1',
   `limit_mailbox` int(11) NOT NULL DEFAULT '-1',
   `limit_mailalias` int(11) NOT NULL DEFAULT '-1',
@@ -184,7 +184,7 @@ CREATE TABLE `client` (
   `limit_spamfilter_user` int(11) NOT NULL DEFAULT '0',
   `limit_spamfilter_policy` int(11) NOT NULL DEFAULT '0',
   `default_webserver` int(11) unsigned NOT NULL DEFAULT '1',
-  `web_servers` blob NOT NULL DEFAULT '',
+  `web_servers` blob NOT NULL,
   `limit_web_ip` text,
   `limit_web_domain` int(11) NOT NULL DEFAULT '-1',
   `limit_web_quota` int(11) NOT NULL DEFAULT '-1',
@@ -206,13 +206,13 @@ CREATE TABLE `client` (
   `limit_webdav_user` int(11) NOT NULL DEFAULT '0',
   `limit_aps` int(11) NOT NULL DEFAULT '-1',
   `default_dnsserver` int(11) unsigned NOT NULL DEFAULT '1',
-  `db_servers` blob NOT NULL DEFAULT '',
+  `db_servers` blob NOT NULL,
   `limit_dns_zone` int(11) NOT NULL DEFAULT '-1',
   `default_slave_dnsserver` int(11) unsigned NOT NULL DEFAULT '1',
   `limit_dns_slave_zone` int(11) NOT NULL DEFAULT '-1',
   `limit_dns_record` int(11) NOT NULL DEFAULT '-1',
   `default_dbserver` int(11) NOT NULL DEFAULT '1',
-  `dns_servers` blob NOT NULL DEFAULT '',
+  `dns_servers` blob NOT NULL,
   `limit_database` int(11) NOT NULL DEFAULT '-1',
   `limit_database_quota` int(11) NOT NULL default '-1',
   `limit_cron` int(11) NOT NULL DEFAULT '0',