Relocates some test infrastructure in preparation for
use with encryption tests, in particular moves the test
server setup code from test/unit/proxy/test_server.py
to a new helpers.py so that it can be re-used, and adds
ability to specify additional config options for the
test servers (used in encryption tests).
Adds unit test coverage for extract_swift_bytes and functional
test coverage for container listings. Adds a check on the content
and metadata of reconciled objects in probe tests.
Change-Id: I9bfbf4e47cb0eb370e7a74d18c78d67b6b9d6645
