tests/test-revert-flags.t

logexchange: convert paths to unix when detecting the active path

This fixes the problem in the tests[1] where Windows was showing the whole path
as the remotename for local repositories.

Somebody with a better understanding of this extension should probably take a
deeper look.  There may be other cases that need to be converted- specifically
the `elif not instance` and the missing `else` cases in activepath().  I also
noticed when adding debug prints that the absolute path is stored in the file,
probably not normalized.  (It's wrapped up in $TESTTMP.)

[1] https://buildbot.mercurial-scm.org/builders/Win7%20x86_64%20hg%20tests/builds/1042/steps/run-tests.py%20%28python%202.7.13%29/logs/stdio

#require execbit

  $ hg init repo
  $ cd repo
  $ echo foo > foo
  $ chmod 644 foo
  $ hg ci -qAm '644'

  $ chmod 755 foo
  $ hg ci -qAm '755'

reverting to rev 0

  $ hg revert -a -r 0
  reverting foo
  $ hg st
  M foo
  $ hg diff --git
  diff --git a/foo b/foo
  old mode 100755
  new mode 100644

  $ cd ..