MINOR: MySQL stub function created for Postgres-specific functionality

git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/sapphire/trunk@115447 467b73ca-7a2a-4603-9d3b-597d59a354a9

core/model/MySQLDatabase.php

@@ -358,6 +358,18 @@ class MySQLDatabase extends SS_Database {
 		return $fieldList;
 	}
 
+	/**
+	 *
+	 * This is a stub function.  Postgres caches the fieldlist results.
+	 *
+	 * @param string $tableName
+	 *
+	 * @return boolean
+	 */
+	function clear_cached_fieldlist($tableName=false){
+		return true;
+	}
+
 	/**
 	 * Create an index on a table.
 	 *