pull: move return code in the pull operation object
With bundle2 we'll have multiple code path susceptible to be responsible for
adding changeset during the pull. We move it to the pull operation to simplify
this the coming logic. The one doing the adding the changegroup will set the
value.
$ "$TESTDIR/hghave" execbit || exit 80
$ hg init repo
$ cd repo
$ echo foo > foo
$ chmod 644 foo
$ hg ci -qAm '644'
$ chmod 755 foo
$ hg ci -qAm '755'
reverting to rev 0
$ hg revert -a -r 0
reverting foo
$ hg st
M foo
$ hg diff --git
diff --git a/foo b/foo
old mode 100755
new mode 100644
$ cd ..