Make cfiscsi_offline() synchronous, waiting for connections termination
before return.  This should make ctld restart more clean and predictable.

MFC after:	2 weeks


git-svn-id: svn+ssh://svn.freebsd.org/base/head@274805 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Add a guard against attempting to invoke the buildenv target with -j# as
that silently exits rather than doing something useful.

MFC after:	1 week
Sponsored by:	DARPA, AFRL


git-svn-id: svn+ssh://svn.freebsd.org/base/head@274806 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f