During cloud-init there are several calls that asks neutron API for the
same data which will not be most likely changed. Specifically router's
networks are cached.
Closes-bug: #1276440
Conflicts:
neutron/tests/unit/test_metadata_agent.py
Change-Id: Ic5eedb8057c7f4934eed08869ebf55c91e6edfc9
(cherry picked from commit 3faea81c60)