Open Stack

Hi all,

During the review of https://review.openstack.org/#/c/36350/ Flavio 
mentioned that I should send something to the ml to notify people of the 
coming change in behavior, so here it is.

The short version is that right now if you use external locking without 
specifying a lock_path in either the decorator or the conf file, you are 
getting no real locking because it creates a new, random lock path for 
each call to the function.  My change is going to throw an exception 
when that happens now because there's no safe way for us to come up with 
a default value that won't be a security risk.

Note that if you were relying on this behavior before, you were 
_already_ broken but didn't know it.  All this change does is make 
broken configurations obvious.

If you have any comments feel free to leave them here or on the review.

Thanks.

-Ben