Only modify folders created by devstack

running chown and chmod on files and folders not created by
devstack causes a few issues:

* On nfs mounted directories it can take an extremely
  long time to chown -R some of the git repos, especially
  if any tox commands have been ran in the host
* chown can cause the host files to get into a weird state
  if nfs is set up wrong.

If files and folders are pre-existing we should assume
they are in the correct state, and not modify them.

Fix setup-devstack-log-dir to create the logs directory with
correct permissions in the first place.

Change-Id: I5ebdaded3ffd0a5bc70c5e9ab5b18daefb358f58
Signed-off-by: Graham Hayes <gr@ham.ie>
3 files changed