Truncate nextboot.conf file on creation, so existing garbage will be removed.
Truncate nextboot.conf file on creation, so existing garbage will be removed.

Submitted by:	Gary Allan <dragonfly@gallan.plus.com>
Obtained from:	DragonFlyBSD
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