use admin email for closed site

services/web/app/views/general/closed.jade

@@ -11,4 +11,4 @@ block content
 						| Sorry, ShareLaTeX is briefly down for maintenance.
 						| We should be back within minutes, but if not, or you have
 						| an urgent request, please contact us at
-						| support@sharelatex.com
+						| #{settings.adminEmail}