add prechangegroup and pretxnchangegroup hooks.
prechangegroup lets you stop push, pull or unbundle before it begins.
pretxnchangegroup lets you inspect changegroup before transaction is
committed, and roll back if you not like it.
changeset: 0:acb14030fe0a
tag: tip
user: test
date: Thu Jan 1 00:00:00 1970 +0000
summary: test
b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 644 a
a
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions