Fix oslo.config and unittest.

Switch to the new oslo.config package which was renamed from
oslo-config.

Use python-keystoneclient master version as a temporary workaround for
bug #1151665.

Temporary workdaround of the bug #1151345 by comment out the test code
to pass the jenkin's gate test.

Change-Id: I7c223f3e98c5d33993b345d93c27f97d3d926d80