Merge branch 'mail_room_timeout' into 'master'

Change the default imap idle timeout of 29 minutes to 60 seconds

This will fix the mail_room hanging issue. Since most IMAP servers are not keeping connections open for 29 minutes. And even when a mailserver support that a firewall in between can stop the connection after X amount of minutes anyway.

See merge request !842

files/gitlab-cookbooks/gitlab/files/default/mail_room.yml

@@ -20,6 +20,7 @@ if Gitlab::IncomingEmail.enabled?
     :start_tls: <%= config.start_tls.to_json %>
     :email: <%= config.user.to_json %>
     :password: <%= config.password.to_json %>
+    :idle_timeout: 60
     :name: <%= config.mailbox.to_json %>