engine_page: set root passwd on oVirt Engine tab

Users must have option to set root password correctly.

Rebase on top of a ConfirmedEntry change.

Change-Id: I56795d2595689c67d078960b3f6e676cd92d9e1f
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=989003
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>