This patch always builds PXE options for booting a user image even if
the provision state is related to rescue mode. When the state is
unrescuing, these options are necessary to boot a user image. When the
provision state is rescuing, these options are just ignored because
the PXE configuration is used at deployment mode.
Change-Id: I1ff51cab120e6612c71e5d9c45cf28797bc16e76
Closes-Bug: 1749433