Different approach to making all compilers happy.
Apply the ad* => ada* IDE device name transition to the Xen block
front driver.

Submitted by:	Bei Guan <gbtju85@gmail.com>
Reviewed by:	gibbs
MFC after:	1 week
Make netif_free() safe to call on a partially initialized softc.

Sponsored by:	Spectra Logic Corporation
MFC after:	1 week