Make password_auth_enabled() take a realm object

This will actually be used in an upcoming commit.

(imported from commit 5d3db685a245899b2523440398f2ed2f0cfec4f4)

zproject/backends.py

@@ -13,7 +13,7 @@ from openid.consumer.consumer import SUCCESS
 from apiclient.sample_tools import client as googleapiclient
 from oauth2client.crypt import AppIdentityError
 
-def password_auth_enabled():
+def password_auth_enabled(realm):
     for backend in django.contrib.auth.get_backends():
          if isinstance(backend, EmailAuthBackend):
              return True