Error when session is not in backend but only in cookie
In trunk code (at least) if a session is not found in backend but present in cookie, the portal cannot be displayed:
[Fri Jun 12 12:37:46.690740 2015] [:error] [pid 22080] Can't use an undefined value as a HASH reference at /usr/share/perl5/Lemonldap/NG/Portal/Simple.pm line 906, <DATA> line 751.\n