Set vnet context before accessing V_socket_hhh[].

Submitted by:	"Hiroo Ono (小野寛生)" <hiroo.ono+freebsd gmail.com>


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271182 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f