lock: update the docstring with order information Lock must be acquired in a specific order to avoid dead-lock. This was documented on the wiki, but having this information in the docstring is also useful.

wlock: reword the devel warning We change the wording of the developer warning: - "lock" taken before "wlock" + "wlock" acquired after "lock" The goals here are to: - Put the "subject" as the first word, - use "acquired" instead of "taken" since it seems more accurate.

wlock: only issue devel warning when actually acquiring the lock Before this change, any call to 'wlock' after we acquired a 'lock' was issuing a warning. This is wrong as the 'wlock' have been properly acquired before the 'lock' in a previous call. We move the warning code to only issue such warnings when we are acquiring the 'wlock' -after- acquiring 'lock'. This is the expected behavior of this warning from the start.