Use oslo.utils and oslo.concurrency

Update openstack/common files and use oslo.utils, oslo.concurrency
instead of modules from oslo-incubator.

Additionally, sort and set requirements.txt to correct versions in
openstack/requirements in order to ensure pep8 passes.

Change-Id: I15f88a31a4c889bba27cd0cd1c7fc481c0c0b51e
Merge "Use oslo.utils and oslo.concurrency"