test that 'hg commit' does not crash if the user removes a newly added file

  $ hg init

  $ echo This is file a1 > a

  $ hg add a

  $ hg commit -m "commit #0"

  $ touch b

  $ hg add b

  $ rm b

  $ hg commit -A -m"comment #1"

  removing b

  nothing changed

  $ exit 0