webadmin: add dash - before every item in the remove brick confirmation pop up

Adding a dash (-) before every item in the remove brick confirmation pop up

Change-Id: I65d43615162ea1274207e49fefcbb270d707d79c
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1024734
Signed-off-by: Ramesh Nachimuthu <rnachimu@redhat.com>