lockutils: add a failing unit test

Add a unit test which fails because of #1107950 - in this case,
lockutils is deleting the lock directory every time the lock is dropped
even though another process might have acquired a lock using that
directory.

Change-Id: Ic82409f9462e570bc102ab469334c53aafc6d7ac
Locking edge case when lock_path does not exist

Fixes bug 1158179

In the case that the lock_path does not exist and there is a contested
resource then the process that was waiting on the lock will not
be locking due to the fact that the directory was deleted.

Change-Id: I75d720d4df499e85386d3e2cc86b927b017e12ac
Merge "lockutils: add a failing unit test"
Merge "Locking edge case when lock_path does not exist"