find method needed for BaseProxy

[Brian Curtin]

In the flurry of changes that happened and didn't happen around Resource.find, we never created a BaseProxy.find method to be used in the various service proxies. Find methods on proxy classes are currently running through the resources themselves instead of through BaseProxy where possible (probably everywhere) like the other operations.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/247265

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/247265
Committed: https://git.openstack.org/cgit/openstack/python-openstacksdk/commit/?id=1ea6243af559d9d82e17c14cf6cf28106016f66b
Submitter: Jenkins
Branch: master

commit 1ea6243af559d9d82e17c14cf6cf28106016f66b
Author: Brian Curtin <email address hidden>
Date: Wed Nov 18 19:55:37 2015 -0600

    Add find support to BaseProxy

    All other actions on the Resource class that are used in Proxy
    subclasses had been exposed in BaseProxy except for find. This change
    implements a simple `_find` in the base, which brings it in line with
    how everything else is done, and is the last piece to get knowledge of
    `self.session` out of proxy calls.

    Additionally, while moving the proxy implementations to all be the same,
    it's a chance to unify the find tests in the proxy. This change
    eliminates the need for there to have been two test methods and makes
    the tests look like how they're done for every other action.

    Change-Id: Ibea01bed4e4ecd76d96021f78db0116012448984
    Closes-Bug: 1517149