Plug a memory leak.

Obtained from:	DragonFlyBSD (commit 5119ece)
MFC after:	2 weeks


git-svn-id: svn+ssh://svn.freebsd.org/base/head@275930 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Fix `make depend` in sys/modules

Differential Revision:	https://reviews.freebsd.org/D1338
Reviewed by:	delphij
Approved by:	delphij


git-svn-id: svn+ssh://svn.freebsd.org/base/head@275931 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f