Fix 1993520 where page cycler fails.

Recover the old logic before removing network management. Remove the empty
list for the host after consuming the last entry. As we should never have
an empty list, it is safe to call removeFirst without checking whether it is
empty.

Currently, in getRequest() or removeFrist(), if we found an empty list, we
remove it. Then we return null for the request even there are requests in
another list. So the page stops loading until the next getRequest() or
removeFirst() is called. If they are not called, those requests will never
be accessed.