tests/test-dirstate-race.t

changegroup: don't use 'repo' for non-repo 'self'

'repo' is a very confusing name to use for 'self', especially when
it's not a repo. Also drop repo.ui member (a.k.a. self.ui) now that
'self' doesn't shadow outer 'repo' variable.

  $ hg init
  $ echo a > a
  $ hg add a
  $ hg commit -m test

Do we ever miss a sub-second change?:

  $ for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20; do
  >     hg co -qC 0
  >     echo b > a
  >     hg st
  > done
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a
  M a