Don't flip out if there are no template hooks

Git may have been installed without its hooks directory, which
means we won't have any hooks in a repo created git repository.
Since we are just deleting the hooks it doesn't matter.

Signed-off-by: Shawn O. Pearce <sop@google.com>
diff --git a/project.py b/project.py
index 46d23f6..120264f 100644
--- a/project.py
+++ b/project.py
@@ -775,7 +775,11 @@
       self.config.SetString('core.bare', None)
 
       hooks = self._gitdir_path('hooks')
-      for old_hook in os.listdir(hooks):
+      try:
+        to_rm = os.listdir(hooks)
+      except OSError:
+        to_rm = []
+      for old_hook in to_rm:
         os.remove(os.path.join(hooks, old_hook))
 
       # TODO(sop) install custom repo hooks