Implements 'bzr lock --config <file>'.
*Â bzrlib/tests/blackbox/test_break_lock.py:
(TestConfigBreakLock): Corresponding tests.
*Â bzrlib/config.py:
(LockableConfig.break_lock):Â Added.
*Â bzrlib/builtins.py:
(cmd_break_lock): Add a --config option.