pytidylib and netifaces should be removed from dependency because they are not required

Fix proposed to branch: master
Review: https://review.openstack.org/149133

Reviewed: https://review.openstack.org/149133
Committed: https://git.openstack.org/cgit/openstack/ceilometer/commit/?id=b483a9ab06e6021ded5fc51d1a003d542f1dd306
Submitter: Jenkins
Branch: master

commit b483a9ab06e6021ded5fc51d1a003d542f1dd306
Author: ZhiQiang Fan <email address hidden>
Date: Thu Jan 22 11:06:55 2015 +0800

    remove pytidylib and netifaces from tox.ini external dependency

    pytidylib is introduced on Jan 27, 2014 by
    commit: 3257d83bbb3e2302638581c995e44d6e84ad44c0,
    changeId: I73f3202ac7a1420aaa303d5ea2e741b2fe5673e9
    https://review.openstack.org/#/c/69491/

    but actually not used, nor used by packages depended by us. The commit
    message, review comments and bug report don't provide details for this
    change.

    netifaces is introduced Jan 21 2014 by:
    commit: 28f6bee013c55ac9f4b4545293fd8849da45c961
    changeId: I1721804890423c242bb69697d2c42ca57d0871a4

    At that time, it is required by swift, but now we have removed swift from
    {test-}requirements.
    Now it is only required by oslo.utils.netutils, but can be downloaded
    via pypi, see:
    https://github.com/openstack/oslo.utils/blob/1.2.0/requirements.txt#L11

    Change-Id: I8bff587892396c32b327049b024e6e8acfff64cf
    Closes-Bug: #1413455