Updated logging of mails that take too long to be sent.

Because in prod we usually switch off all the logs until WARN, it's better
tell admins about big problems with performance (like mails that take
more than 30 secs).
Merge branch 'master' of https://github.com/jtalks-org/jcommune
Revert "#JC-1533 Initial implementation of the "Edit Permissions" dialog for the Branch"

This reverts commit 06fce72640b4ea008e6831ec85e4510473bebaad.