tests/test-rebuildstate.t

patchbomb: make it easy for the user to decline sending an intro message.

- prompt(): respect interactive mode; clarify logic a bit
- rename introneeded() to introwanted() and give it only one caller
- add 'numbered' arg to makepatch() so it does not need to call
  introwanted()
- factor makeintro() out of getpatchmsgs(), so it's easier to skip the
  intro message based on the user's behaviour

Unexpected but perfectly reasonable side effect: in non-interactive
mode, we don't show unanswerable "Cc" or "From" prompts anymore, so
remove those from the test expectations.

basic test for hg debugrebuildstate

  $ hg init repo
  $ cd repo

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

  $ touch baz
  $ hg add baz
  $ hg rm bar

  $ hg debugrebuildstate

state dump after

  $ hg debugstate --nodates | sort
  n 666         -1 bar
  n 666         -1 foo

status

  $ hg st -A
  ! bar
  ? baz
  C foo