convert: return remote branches in git source

When converting git repos, all stuff happening on branches
seems to be ignored.

This is caused by the fact a "git clone" of a remote git
repo has all its branches prefixed with "origin/". By
chance, the "origin/master" branch is always linked to a
local "master" branch. So getheads() returns only the
master head, and it ignores all the other heads.

Make sure getheads() returns all heads, forcing remote
branches to be return by git-rev-parse.

hgext/convert/git.py

@@ -38,7 +38,7 b' class convert_git(converter_source):'
 
     def getheads(self):
         if not self.rev:
-            return self.gitcmd('git rev-parse --branches').read().splitlines()
+            return self.gitcmd('git rev-parse --branches --remotes').read().splitlines()
         else:
             fh = self.gitcmd("git rev-parse --verify %s" % self.rev)
             return [fh.read()[:-1]]