webadmin: Fix for stop/status rebalance issue

  This patch fixes following bugs.
1. Showing volume names on the stop rebalance confimation dialog
2. Cancel button not working stop rebalance confirmation

Change-Id: Ia0c6a8fdc6a74134cf2fccec11e941d151355a92
Bug-Url:https://bugzilla.redhat.com/show_bug.cgi?id=1021334
Signed-off-by: Ramesh Nachimuthu <rnachimu@redhat.com>