tests/test-unbundlehash.t

import: wrap a transaction around the whole command

Now 'rollback' after 'import' is less surprising: it rolls back all of
the imported changesets, not just the last one. As an extra added
benefit, you don't need 'rollback -f' after 'import --bypass', which
was an undesired side effect of fixing issue2998 (59e8bc22506e)..

Note that this is a different take on issue963, which complained that
rollback after importing multiple patches returned the working dir
parent to the starting point, not to the second-last patch applied.
Since we now rollback the entire import, returning the working dir to
the starting point is entirely logical. So this change also undoes
a732eebf1958, the fix to issue963, and updates its tests accordingly.

Bottom line: rollback after import was weird before issue963,
understandable since the fix for issue963, and even better now.

Test wire protocol unbundle with hashed heads (capability: unbundlehash)

Create a remote repository.

  $ hg init remote
  $ hg serve -R remote --config web.push_ssl=False --config web.allow_push=* -p $HGPORT -d --pid-file=hg1.pid -E error.log -A access.log
  $ cat hg1.pid >> $DAEMON_PIDS

Clone the repository and push a change.

  $ hg clone http://localhost:$HGPORT/ local
  no changes found
  updating to branch default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ touch local/README
  $ hg ci -R local -A -m hoge
  adding README
  $ hg push -R local
  pushing to http://localhost:$HGPORT/
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files

Ensure hashed heads format is used.
The hash here is always the same since the remote repository only has the null head.

  $ cat access.log | grep unbundle
  * - - [*] "POST /?cmd=unbundle HTTP/1.1" 200 - x-hgarg-1:heads=686173686564+6768033e216468247bd031a0a2d9876d79818f8f (glob)