userportal,webadmin: select first element on changing list

- When removing all elements except one, the code that tries to
  auto select kicked in and would select the first element of
  the old list giving an illusion of duplicates for a split
  second. This patch fixes this by not auto selecting the only
  element immediately, but deferring it until the operation has
  completed and the list has been updated.

Change-Id: Ib1ccea11f00bbf21e5fd63d4293075152d25cb1d
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1131881
Signed-off-by: Alexander Wels <awels@redhat.com>