lorry: Create bare repository in gitify_cvs

Since commit 50383f3bcce7 "lorry: Crash-proof updates to working git
repos with A/B switching", prepare_working_repos assumes that the
existing working repositories are bare.  Most gitify functions ensure
that, but gitify_cvs does not.

* Specify the git directory to "git cvsimport" using $GIT_DIR, not
  the -C option (which specifies a working tree)
* Add the -i option to inhibit it from checking out a working tree
* Delete any index file that it creates

Closes #12.

1 files changed, 9 insertions, 2 deletions

diff --git a/lorry b/lorry
index 279a175..59d8296 100755
--- a/lorry
+++ b/lorry
@@ -681,11 +681,18 @@ class Lorry(cliapp.Application):
         self.needs_aggressive = True
         env = dict(os.environ)
         env['CVS_RSH'] = 'lorry-ssh-wrapper'
+        env['GIT_DIR'] = gitdir
         self.run_program(
-            ['git', 'cvsimport', '-a', '-d', spec['url'], 
-             '-C', gitdir, spec['module']],
+            ['git', 'cvsimport', '-a', '-d', spec['url'],
+             '-i', spec['module']],
             env=env)
 
+        # git cvsimport may create an index even in a bare repo
+        try:
+            os.remove(os.path.join(gitdir, 'index'))
+        except FileNotFoundError:
+            pass
+
     def gitify_hg(self, project_name, dirname, gitdir, spec):
         cert_options = []
         if not self.should_check_certificates(spec):