Handle all HTTP exceptions

Signed-off-by: Michal Čihař <michal@cihar.com>
Store original exception as well

Signed-off-by: Michal Čihař <michal@cihar.com>
Workaround for bad login cookies

Sometimes accessmanager turns every request to 502: Bad Gateway, what
can be ususally cleared by removing cookies and logging in again.

Signed-off-by: Michal Čihař <michal@cihar.com>