Fix traceback when nothing was added during unbundle
The changegroup and commit hook are now run only when
something is modified.
The correct number of changesets added is printed.
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions
changeset: 0:acb14030fe0a
tag: tip
user: test
date: Thu Jan 1 00:00:00 1970 +0000
summary: test
rolling back last transaction
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
0 files, 0 changesets, 0 total revisions
A a