subrepo: use repo['.'] instead of repo['']
The "state" value (a revision) passed to abstractsubrepo.phase() can
be '' to represent the currently checked out revisions. Let's convert
that to the more common '.'.
I think this is the last of use of repo['.'] in core.
Differential Revision: https://phab.mercurial-scm.org/D3019
--- a/mercurial/subrepo.py Tue Apr 03 00:12:29 2018 +0530
+++ b/mercurial/subrepo.py Mon Apr 02 08:43:08 2018 -0700
@@ -603,7 +603,7 @@
@annotatesubrepoerror
def phase(self, state):
- return self._repo[state].phase()
+ return self._repo[state or '.'].phase()
@annotatesubrepoerror
def remove(self):