webadmin: fix remove brick status error message

  Fixing the error message displayed when remove brick
status is failed. Error message lists the bricks name instead
of volume name. Corrected it to show the volume name.

Change-Id: I8f66f7c7703d5ee6977375f33993a23e1c8d2677
Bug-Url: https://bugzilla.redhat.com/1035146
Signed-off-by: Ramesh Nachimuthu <rnachimu@redhat.com>