OS-3062 Reign in copypasta nature of brand code
OS-3076 brand statechange never emits failure
OS-2999 vmadm could support jumbo frames
OS-3063 nictagadm needs to learn about the mtu
OS-3057 Need a way to set the MTU of a device at boot time
Reviewed by: Rob Gulewich <robert.gulewich@joyent.com>
Reviewed by: Josh Wilsdon <jwilsdon@joyent.com>