Need method to detect and break bzr locks

[Nathan Handler]

I recently attempted to use the 'Update' button to update a branch previously created with groundcontrol. After waiting a long time for it to synchronise, I received a "Could not acquire lock" bazaar error message. I ran 'bzr break-lock' in a terminal to break the lock. I was then able to run the 'Update'. Groundcontrol should have a method of detecting these locks and providing the user with the ability to break the lock.

[Martin Pool (mbp)]

You can use lockdir.peek() to see if it's already held and to get some information.

Really the locking stuff should be lifted to the uifactory, then you can do this in a more structured way.