[merge] change commit to use update_to_one_parent_via_delta; other fixes

[Martin Pool]

This updates commit to the new wt api recently added by Robert,
update_to_one_parent_via_delta.  The idea is that after the commit we
do an update to the workingtree's basis information to just tell it
about the changes, rather than rebuilding the whole thing.

The main change that had to be made was that some commit builders were
changing the root entry's revision property, but not including that in
the delta they pass back.

At the moment update_to_etc has a rudimentary implementation that
makes an inventory, applies the delta, and writes it back.  So this is
actually 20% slower at present for an incremental commit in a large
tree, but I'd still appreciate a review for correctness.

-- 
Martin
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 20071012-commit-update-delta.diff
Type: text/x-diff
Size: 15596 bytes
Desc: not available
Url : https://lists.ubuntu.com/archives/bazaar/attachments/20071012/ef9ad5f8/attachment-0001.bin