webadmin: Fix findbugs issue in HostGeneralModel

Fixes findbugs issues in HostGeneralModel introduced in patch
I16254bd36c36ee241280598203464237cf7e00c7

Change-Id: Ie0f0cf94d47c3d5a6a401d9edc70067628c04f80
Signed-off-by: Martin Perina <mperina@redhat.com>