If the local account is disabled user can't log in via federation,
(redirect to root path and flash an error)

refs #1312
Merge PR #35 of git://github.com/gmiotto/mconf-web

refs #1312
Improvements on PR #35, blocking disabled users from shib sign in

Refactoring in the shibboleth controller. Works just as before, just
organized in a different way.
Added more tests also.

refs #1312