userportal,webadmin: Change remove message

- Change the 'Are you sure you want to remove the following
{0}?' with 'Are you sure you want to remove the following
items?'

Change-Id: Ia934e33d1a975e0235e1a1ffae0c8a4a7af66f10
Signed-off-by: Alexander Wels <awels@redhat.com>