tests/test-revlog-packentry.t

graft: store user passed date and user information in graftstate

Right now, `hg help graft` says:

The -c/--continue option does not reapply earlier options, except for --force.

which should be treated as a bug.

A good user experience is that the commands remember the arguments passed
initially and preserve them during `hg graft --continue`.

This patch starts storing the user and date information in graftstate if user
passed it. Upcoming patches will make sure we preserve that information during
--continue and them don't allow user to pass any new arguments with --continue.

I don't think there is any another `--continue` flag which allows new options to
be passed with it.

Differential Revision: https://phab.mercurial-scm.org/D3657

  $ hg init repo
  $ cd repo

  $ touch foo
  $ hg ci -Am 'add foo'
  adding foo

  $ hg up -C null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

this should be stored as a delta against rev 0

  $ echo foo bar baz > foo
  $ hg ci -Am 'add foo again'
  adding foo
  created new head

  $ hg debugindex foo
     rev linkrev nodeid       p1           p2
       0       0 b80de5d13875 000000000000 000000000000
       1       1 0376abec49b8 000000000000 000000000000

  $ cd ..