Offline membership form script error when outbound email disabled

When outbound email is disabled in System Settings, the offline membership form encounters a javascript error leading to loss of form functionality.

The problem is in CRM_Membership_Form_Membership::buildQuickForm() with this statement:

    $this->assign('isEmailEnabledForSite', ($mailingInfo['outBound_option'] != 2));

When outbound mail is disabled (option 2) then the Smarty variable is assigned FALSE. This variable is used in the corresponding template as follows:

      var isEmailEnabledForSite = {$isEmailEnabledForSite};

This results in a javascript syntax error:

      var isEmailEnabledForSite = ;

The fix is to assign the value 0 instead of FALSE:

    $this->assign('isEmailEnabledForSite', ($mailingInfo['outBound_option'] != 2) ? 1 : 0);