ux: allow using password authentication on foreman hosts

Previous patch removed the ability to use password
authentication with external hosts provided by Foreman.
This patch fixes that issue by hiding this option only
when installation relevant properties are to be hidden.

Change-Id: I26e351f0560ac4fe8f45ec2314ef4a6aa7ddafb9
Bug-Url: https://bugzilla.redhat.com/1079072
Signed-off-by: Oved Ourfali <oourfali@redhat.com>