userportal: fix motd

- Fixed MOTD panel being modal and disabling the rest
  of the dialog.
- Fixed flicker of MOTD panel when you have no MOTD.
- Fixed MOTD showing during login process if you have
  a MOTD set.

Change-Id: I048cdf6029617dda39357d876abd250bf9ae9a46
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1063041
Signed-off-by: Alexander Wels <awels@redhat.com>