tests/test-issue433.t

statichttprepo: abort if opener mode is 'r+' or 'rb+'

The old version of the check failed to catch
modifying modes 'r+' and 'rb+'.

http://mercurial.selenic.com/bts/issue433

  $ hg init
  $ echo a > a
  $ hg commit -Ama
  adding a

  $ hg parents -r 0 doesnotexist
  abort: 'doesnotexist' not found in manifest!
  [255]