lockutils: remove lock_path parameter

This remove the parameter lock_path so the configured lock_path is
always used instead. There's only a few places where this is used in
OpenStack, and it's not heavily justified to have it even in this
places.

This is needed to simplify the interface toward moving to IPC locking
mechanism. With such a locking mechanism in place, the lock_path
parameter has absolutely no sense. So isolating this to make it only
relevant to some part of the driver and not in the public interface
makes more sense.

Change-Id: I72bd683209090ae6e3911a709e4d213879508aca
Blueprint: lockutils-posix-ipc
lockutils: move directory creation in lock class

We are going to implement a lock mechanism that does not rely on file
path at all, so there's no need to create such a hierarchy in advance.
Let's do that job in the class actually implementing the external lock
mechanism.

Change-Id: Ibd55ef6ee517f615dd6b398ebe72d1c6552f4675
Blueprint: lockutils-posix-ipc
Merge "lockutils: remove lock_path parameter"
Merge "lockutils: move directory creation in lock class"