sbin/hammer: Abort if a device is used for more than one volumes

sbin/hammer: Abort if a device is used for more than one volumes

- setup_volume() needs to check if the device has already been
  registered, in addition to checking the volume id. If it's been
  registered already, abort the process before writes to volumes
  start. Otherwise using a single device for more than one volumes
  hits assertion at some point on blockmap lookup of layer1/2
  bigblocks with possible core dump. It should abort before any
  ondisk change (when the function is used by newfs_hammer) occurs.

  # /sbin/newfs_hammer -L TEST /dev/da3 /dev/da3 /dev/da3
  Volume 0 DEVICE /dev/da3        size 465.76GB
  newfs_hammer: setup_volume: /dev/da3: Specified more than once