Remove backticks for MSSQL compatibility

Errors are seen on the Home page for some users, even with Twitter/FB connectors disabled.

"SQL Error : Incorrect syntax near '`'.SQL Error : Incorrect syntax near '`'.SQL Error : Incorrect syntax near '`'.SQL Error : Incorrect syntax near '`'."

More details here:https://suitecrm.com/index.php?option=com_kunena&view=topic&catid=7&id=2174&Itemid=1136