When "jail -c vnet" request fails, the current code actually creates and leaves behind an orphaned vnet.  This change ensures that such vnets get released.
When "jail -c vnet" request fails, the current code actually creates and
leaves behind an orphaned vnet.  This change ensures that such vnets get
released.

This change affects only options VIMAGE builds.

Submitted by:	jamie
Discussed with:	bz
Approved by:	re (rwatson), julian (mentor)
MFC after:	3 days

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase