commit: make commit acquire store lock before processing for consistency If acquisition of wlock waits for another "hg commit" process to release it, dirstate will refer newly committed revision after acquisition of wlock. At that time, '00changelog.i' on the filesystem contains this new revision, but in-memory 'repo.changelog' doesn't, if it is cached without store lock (slock) before updating by another "hg commit". This makes validating parents at re-loading 'repo.dirstate' from '.hg/dirstate' replace such new revision with 'nullid'. Then, 'localrepository.commit()' creates "orphan" revision (see issue4368 for detail). a01d3d32b53a makes 'commands.commit()' acquire both wlock and slock before processing to avoid this issue at "hg commit". But similar issue can occur even after a01d3d32b53a, if 3rd party extension does: - refer 'repo.changelog' outside wlock scope, and - invoke 'repo.commit()' directly (instead of 'commands.commit()') This patch makes 'commit()' acquire slock before processing, to refer recent changelog at validating parents of 'repo.dirstate'.