database: Reintroduce the variables used in Power Saving policy

One patch introduced a regression and removed HostsInReserve and
EnableAutomaticPowerManagement policy variables from the db.

Change-Id: I48040a9c9ec1873872c789cf07c51a5489b3e65c
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1092623
Signed-off-by: Martin Sivak <msivak@redhat.com>