version: add remote tracking information

This tells us what --repo-rev the user is using.

Bug: https://crbug.com/1164415
Change-Id: Idb6c48e6ca5a4783c529717e6be38266bf7038b0
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/293143
Reviewed-by: Michael Mortensen <mmortensen@google.com>
Tested-by: Mike Frysinger <vapier@google.com>
diff --git a/subcmds/version.py b/subcmds/version.py
index 000abf0..e95a86d 100644
--- a/subcmds/version.py
+++ b/subcmds/version.py
@@ -33,12 +33,14 @@
   def Execute(self, opt, args):
     rp = self.manifest.repoProject
     rem = rp.GetRemote(rp.remote.name)
+    branch = rp.GetBranch('default')
 
     # These might not be the same.  Report them both.
     src_ver = RepoSourceVersion()
     rp_ver = rp.bare_git.describe(HEAD)
     print('repo version %s' % rp_ver)
     print('       (from %s)' % rem.url)
+    print('       (tracking %s)' % branch.merge)
     print('       (%s)' % rp.bare_git.log('-1', '--format=%cD', HEAD))
 
     if self.wrapper_path is not None: