Revert "Use tempfile.tempdir for lock_path if OSLO_LOCK_PATH is not set"
Revert "Use tempfile.tempdir for lock_path if OSLO_LOCK_PATH is not set"

This reverts commit 5021ef82fd8f0323b82d6d010bff9dab8a0cbcec.

That commit set default location for lock files to a world-writable
directory (like /tmp) which violates security precaution stated right in
the help string of lock_path config variable: lock_path should be
writable by the user of the process using it only.

There is some history behind this:

- when we decided to not do tempfile.mkdtemp if lock_path were not set
  (because it was broken), it broke upgrades for all components
  (starting with Cinder;
- it was suggested to provide the same default value:
  https://review.openstack.org/60274
  but it was not accepted because it weakens security;
- there was a thread about this in ML, please read it for more history:
  http://lists.openstack.org/pipermail/openstack-dev/2013-December/021055.html
  it ended up with understanding that only a project using the library
  can provide sane default value for lock_path, not the library itself.

Change-Id: I801004ad3c83862849696f00c6e7ca9877fd496b

openstack/oslo.concurrency