webadmin: Changed Boolean argument to boolean

There was no reason to ever pass null rather than true or false, and
no code called these constructors with a null value.

Change-Id: Ib99896c52b950dcf56891c5e6e2e8b7b760bc830
Bug-Url: https://bugzilla.redhat.com/990612
Signed-off-by: Lior Vernia <lvernia@redhat.com>