I8badc249ad021fdbdb2367b5416c72435ed58994 causes anything importing
neutron/tests/unit/services/vpn/device_drivers/_test_cisco_csr_rest.py
to exit since httmock isn't a dependency.
Fix all hacking issues in addition to the revert, as this patch fixes 'tox -epep8'.
And just a reverting the patch will cause pep8 to fail.
Fixes-Bug: #1340881
This reverts commit 7f0a8f09ab7867100081a898347a5f901e5a442b.
Change-Id: I373a8c8ab16eb387be6a451b8146642389081afa