Revert 1.7.2.1: vlan(4) does use mbuf_tags(9) in RELENG_6.
Revert 1.7.2.1: vlan(4) does use mbuf_tags(9) in RELENG_6.

Noticed by:	Alexander V. Chernikov

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase