webadmin: Password field is not validate on host install

When the host is reinstalled and the password is
choosen as authntication mechanism, empty password
should display an error.

If the user is on Network tab the general tab is selected
and the field is highlighted in red indicating that
it can't be empty.

Change-Id: I3745852a0b1b33e5ba04583e911bbbc90fd8d796
Bug-Url: https://bugzilla.redhat.com/1086798
Signed-off-by: Ravi Nori <rnori@redhat.com>