Fix encryption + remembered login due to missing login hook

The encryption app relies on the post_login hook to initialize its keys.
Since we do not emit it on a remembered login, the keys were always un-
initialized and the user was asked to log out and in again.
This patch *translates* the postRememberedLogin hook to a post_login
hook.

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>