MFp4: @181627

Allow UMA allocated memory to be freed when VNET jails are torn down.

Differential Revision: D1201
Submitted by: bz
Reviewed by: rwatson, gnn


git-svn-id: svn+ssh://svn.freebsd.org/base/head@275555 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f