Change ListOpt default value from str or None to list

In keystone/common/config.py, some ListOpt config object was inited
with a string or None default value, it's incorrect. This patch modifies
their default value to list objects.

Change-Id: I2aec4f49d94e131d45f7dc9bfeb63b8d819d0bb1
Closes-Bug: #1259735
Tests use cleanUp rather than tearDown

The tests were putting clean-up code in tearDown. Using tearDown
causes problems with developing and testing because if there's an
exception raised in setUp then tearDown is not called and this
typically affects other tests. For example, you'll get several
tests failing because one test's setUp failed and now the other
tests can't load fixtures.

Also, this should make it easier to switch to using fixtures since
fixtures use cleanUp.

Change-Id: I0d0d14ec34ebbeb9dbf0fe2fe3dd304b868bcf93
Merge "Change ListOpt default value from str or None to list"
Merge "Tests use cleanUp rather than tearDown"