core: LocalAdminPassword exception after engine restart

After oVirt host comes up from reboot, we see
javax.crypto.BadPaddingException: Data must start with zero
exception in engine.log:

Change-Id: I3eb388c1cc806bdf190ceea7da222e1aa1843c52
Bug-Url: https://bugzilla.redhat.com/994454
Signed-off-by: Ravi Nori <rnori@redhat.com>