CRM-2406 Remove ts('CiviMail') in some of the CRM/Mailing/Menu.php items

In the file CRM/Mailing/Menu.php, the "ts()" should be removed on the 'adminGroup' => ts('CiviMail') lines.

In installations where CiviMail is translated (i.e. in fr_CA, it becomes CiviCourriel), this means that the CiviMail menu items are not shown in the CiviCRM admin page.

In other modules, such as CiviMember, there is no ts() on those items. It seems to affect only CiviMail.

Thanks,

Mathieu Lutfy
Réseau Koumbit, Inc.