tests/test-changelog-exec.t

changegroupsubset: more minor cleanups

 - remove more excessive comments
 - simplify some sorting operations
 - rename some variables
 - replace identity with a lambda

b51a8138292a introduced a regression where we would mention in the
changelog executable files added by the second parent of a merge. Test
that that doesn't happen anymore

  $ "$TESTDIR/hghave" execbit || exit 80

  $ hg init repo
  $ cd repo
  $ echo foo > foo
  $ hg ci -qAm 'add foo'

  $ echo bar > bar
  $ chmod +x bar
  $ hg ci -qAm 'add bar'

manifest of p2:

  $ hg manifest
  bar
  foo

  $ hg up -qC 0
  $ echo >> foo
  $ hg ci -m 'change foo'
  created new head

manifest of p1:

  $ hg manifest
  foo

  $ hg merge
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m 'merge'

this should not mention bar:

  $ hg tip -v
  changeset:   3:ef2fc9b4a51b
  tag:         tip
  parent:      2:ed1b79f46b9a
  parent:      1:d394a8db219b
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  description:
  merge
  
  

  $ hg debugindex .hg/store/data/bar.i
     rev    offset  length   base linkrev nodeid       p1           p2
       0         0       5      0       1 b004912a8510 000000000000 000000000000