The code no longer references the updated_routers and removed_routers
sets. This should have been cleaned up before but was missed.
Closes-bug: #1232525
Change-Id: I0396e13d2f7c3789928e0c6a4c0a071b02d5ff17
(cherry picked from commit edb26bfcddf9d9a0e95955a6590d11fa7245ea2b)