NPE when removing empty tracked request

When there is setup network issue there is an attempt to remove tracked
request and when there are no items on the list we get NPE.

Bug-Url: https://bugzilla.redhat.com/1176407
Bug-Url: https://bugzilla.redhat.com/1175824
Change-Id: If99a51073720ee2273ec2f8ca4f7104543393556
Signed-off-by: pkliczewski <piotr.kliczewski@gmail.com>