Don't call self.load() from registry.register() to avoid recursion.

Presently registry.load() imports provider modules, and each module calls
registry.register(), which itself calls self.load().  The result is that
self.load() attempts to import the entire list of modules once for each
provider module that calls registry.register().

The recursion doesn't hurt because already-imported modules don't run again,
but it would be better to avoid it, and there's no reason for 
registry.register() to call self.load()

commit b19fad7921a7a0106c7a93f6d684d86471750364 Author: Aron Griffis
<aron@arongriffis.com> Date:   Mon Mar 3 19:00:44 2014 -0500

    Don't

diff --git a/allauth/socialaccount/providers/__init__.py
b/allauth/socialaccount/providers/__init__.py index fde92d1..d30141a 100644
--- a/allauth/socialaccount/providers/__init__.py
+++ b/allauth/socialaccount/providers/__init__.py
@@ -11,7 +11,6 @@ class ProviderRegistry(object):
        return self.provider_map.values()

     def register(self, cls):
-        self.load()
        self.provider_map[cls.id] = cls()

     def by_id(self, id):