Protected Hired Merchant + Buff system patch

Fixed some issues with Fredrick not retrieving the right amount of items
from Hired Merchants. Added concurrency protection for HM. Patched a
minor issue on buff system.

sql/db_database.sql

@@ -12984,6 +12984,15 @@ CREATE TABLE IF NOT EXISTS `inventoryitems` (
   KEY `CHARID` (`characterid`)
 ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;
 
+CREATE TABLE IF NOT EXISTS `inventorymerchant` (
+  `inventorymerchantid` int(10) unsigned NOT NULL AUTO_INCREMENT,
+  `inventoryitemid` int(10) unsigned NOT NULL DEFAULT '0',
+  `characterid` int(11) DEFAULT NULL,
+  `bundles` int(10) NOT NULL DEFAULT '0',
+  PRIMARY KEY (`inventorymerchantid`),
+  KEY `INVENTORYITEMID` (`inventoryitemid`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;
+
 CREATE TABLE IF NOT EXISTS `ipbans` (
   `ipbanid` int(10) unsigned NOT NULL AUTO_INCREMENT,
   `ip` varchar(40) NOT NULL DEFAULT '',