Switch if_vlan(4) to rmlock.

MFC after:	2 weeks


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271544 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Do not set net.inet.ip.{sourceroute,accept_sourceroute} in a vnet jail.
The following warnings were displayed:

 sysctl: net.inet.ip.sourceroute=0: Operation not permitted
 sysctl: net.inet.ip.accept_sourceroute=0: Operation not permitted


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271545 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f