CRM-15431 - CRM_Core_I18n - Use CRM_Core_DAO::escapeString for typical, runtime escaping

The call from CRM_Core_I18n breaks on systems that use "mysqli" without
"mysql." Such systems cannot be fully supported for development using
current dataflows (i.e.  "GenCode" won't work), but this patch may make them
usable for regular installations.