switch dircleanup in mercurial.hg.clone from gc based to explicit

switch lock releasing in the core from gc to explicit

made repo locks recursive and deprecate refcounting based lock releasing all locks should use the explicit lock.release mercurial.lock.lock.__del__ handles unwrapping recursive locks localrepo.lock/wlock are still using weakref in order to keep backward compatibiltiy to releasing locks via garbage collection by ensuring the release on __del__