Switch to oslo.config.
Switch to oslo.config.

The oslo-config package has been renamed. Switch to the new
version. (should fix SmokeStack).

Change-Id: Ied8804035d748932e7763cbaa9a7e295a887f1f5

klmitch/python-keystoneclient,jamielennox/python-keystoneclient,sdpp/python-keystoneclient,alexpilotti/python-keystoneclient,alexpilotti/python-keystoneclient,jamielennox/python-keystoneclient,klmitch/python-keystoneclient,ging/python-keystoneclient,sdpp/python-keystoneclient,ntt-sic/python-keystoneclient,darren-wang/ksc,darren-wang/ksc,magic0704/python-keystoneclient,Mercador/python-keystoneclient,metacloud/python-keystoneclient,Mercador/python-keystoneclient,citrix-openstack-build/python-keystoneclient,ntt-sic/python-keystoneclient,citrix-openstack-build/python-keystoneclient,magic0704/python-keystoneclient,ntt-sic/python-keystoneclient,jamielennox/python-keystoneclient,metacloud/python-keystoneclient,citrix-openstack-build/python-keystoneclient,ging/python-keystoneclient