restapi - Fix Display VM Session Info (#894027)

Display VM Sesion info was broken due to changes in the way session info is
stored in the database. This patch fixes that.

Bug-Url: https://bugzilla.redhat.com/894027
Change-Id: I034c93fe0c5037771dc9ed12d64ca5deea10957f
Signed-off-by: Ori Liel <oliel@redhat.com>