Clear BOOTIF at the end of a TUI install if it's set

TUi installs over PXE should not set OVIRT_BOOTIF persistently,
since it may appear as if the network has been configured
prematurely.

Change-Id: I8483280ac36d5511931808a0bc8ee4bce91b32d3
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=989336
Signed-off-by: Ryan Barry <rbarry@redhat.com>
defaults: Fix incorrect Config

Change-Id: Ia61be3b517417f7ccaabc62861034affec9baed1
Signed-off-by: Fabian Deutsch <fabiand@fedoraproject.org>