Fix CF ERASE breakage caused by 268205.

This prevents BIO_DELETE requests getting stuck in the TRIM queue which
results in a panic on shutdown due to outstanding requests.

PR:		194606
Reported by:	Guido Falsi
Reviewed by:	mav
MFC after:	3 days
Sponsored by:	Multiplay


git-svn-id: svn+ssh://svn.freebsd.org/base/head@273704 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f