Change initStatements to charset option when create db connection.

[forfin]

• This option pass to Zend_Db_Adapter_Pdo_Abstract (parent of Mage_Core_Model_Resource_Type_Db_Pdo_Mysql) when init new PDO
• SET NAMES utf8 might be there as a workaround for php < 5.3.6 but should not be a case anymore.
• Ref
  • https://stackoverflow.com/questions/4361459/php-pdo-charset-set-names
  • https://stackoverflow.com/questions/1650591/whether-to-use-set-names

*When Openmage start. It seems to merge every etc/*.xml config including this file. So before this commit, end-user who want to remove initStatements must explicitly set empty to <initStatements /> in later file. Otherwise it still be there.

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