walkdirs test fail when atime is slightly different

[Jelmer Vernooij]

FAIL: breezy.tests.per_workingtree.test_walkdirs.TestWalkdirs.test_walkdir_from_dir(GitWorkingTreeFormat)
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Traceback (most recent call last):
testtools.testresult.real._StringException: Empty attachments:
  log

Traceback (most recent call last):
  File "/<<PKGBUILDDIR>>/breezy/tests/per_workingtree/test_walkdirs.py", line 163, in test_walkdir_from_dir
    self._test_walkdir(self.added, 'added dir')
  File "/<<PKGBUILDDIR>>/breezy/tests/per_workingtree/test_walkdirs.py", line 146, in _test_walkdir
    self.assertEqual(item, result_pos)
  File "/<<PKGBUILDDIR>>/breezy/tests/__init__.py", line 1317, in assertEqual
    pprint.pformat(a), pprint.pformat(b)))
AssertionError: not equal:
a = ((u'added dir', 'git:added_sdir'),
 [(u'added dir/a file',
   'a file',
   'file',
   posix.stat_result(st_mode=33204, st_ino=9577167L, st_dev=2065, st_nlink=1, st_uid=113, st_gid=117, st_size=29L, st_atime=1542684702, st_mtime=1542684702, st_ctime=1542684702),
   'git:added_sdir/a_sfile',
   'file')])
b = ((u'added dir', 'git:added_sdir'),
 [(u'added dir/a file',
   u'a file',
   'file',
   posix.stat_result(st_mode=33204, st_ino=9577167L, st_dev=2065, st_nlink=1, st_uid=113, st_gid=117, st_size=29L, st_atime=1542684703, st_mtime=1542684702, st_ctime=1542684702),
   'git:added_sdir/a_sfile',
   'file')])