Remove two sets that are not referenced

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)
Merge "Remove two sets that are not referenced" into proposed/juno