Mark xennet.sys as boot-critical to simplify offline installation

Explicitly mark the xennet driver as boot-critical using the
"BootCritical=1" directive.  This causes dism.exe to reflect the
driver when performing an offline installation, thereby making it
available on the next boot (which may be an iSCSI boot, requiring a
functioning network).

This avoids the need to hack the registry to manually install the
driver (by creating the HKLM\CurrentControlSet\Services\xennet key and
corresponding entries in the CriticalDeviceDatabase).

Signed-off-by: Michael Brown <mbrown@fensystems.co.uk>
Promote xennet.sys to be a boot start driver on network boot

As a network driver, the NDIS coinstaller will normally set BootFlags
for xennet.sys.  The NDIS coinstaller does not run when performing an
offline installation.  Add BootFlags explicitly using an AddReg
directive (as is done with xenvif.sys) to allow the driver to be
available on the next boot (which may be an iSCSI boot, requiring a
functioning network).

Signed-off-by: Michael Brown <mbrown@fensystems.co.uk>
Merge pull request #14 from mcb30/offline

Ok. Good enough for me. I'll fix up the BootFlags to be 0x81.

BTW; we're going to be concentrating on the new 'upstream' source base from now on. Have a look on http://xenbits.xen.org/gitweb/ at the repos under pvdrivers/win. There's a new sub-project frontpage at http://xenproject.org/developers/teams/windows-pv-drivers.html. I'm just working on a blog entry to kick things off, but the mailing list is already there so feel free to post to it.