Revert upgrading of cinder-rootwrap config

Commit 388c5382cfa099a4bfb096ce66f9473f76a86f48 added the refresh of
cinder-rootwrap config on upgrade from havana to icehouse.

However, the final model used for migration to oslo.rootwrap is seamless
and does not require changes in cinder configuration, so this is
actually useless.

Change-Id: I4a629ba3b83f2518b5033899c5aa1180be471e34
Adding the prep_cache_dir function

Adding the prep_cache_dir function from the
https://review.openstack.org/#/c/74297.

Change-Id: I9b725608fb76406192481e258b00ae822531d16e
Add space at end of target_services to fix partial-ncpu test

Add space at end of TARGET_SERVICES, so when we append services to it
the first two don't get concatenated together.

Change-Id: Iac7025eb70f35746534029dc4bb174f265988416
Merge "Revert upgrading of cinder-rootwrap config"
Merge "Add space at end of target_services to fix partial-ncpu test"
Merge "Adding the prep_cache_dir function"