Remove Routes from requirements
Remove Routes from requirements

This was introduced in the very first commit for requirments (change
Ib62c6ab685c1bcf14ed363031010c4a145098df6) with comment:
"Needed by oslo.common" - with the end of oslo-incubator this is not
valid anymore. No code currently in tree uses "routes", so remove the
requirement.

Change-Id: I952f7e765bdb642f2e12758558498166322e3861

openstack/designate,openstack/designate,openstack/designate