[storage,refactor][xs]: remove slightly weird method caching of ofs i…

…mpl object on 'storage' package, relocating it to ofs property on controller where it is used.

* Main motivation was to avoid errors on startup (e.g. use of paster serve in development mode) of form::
  return GSConnection(gs_access_key_id, gs_secret_access_key, **kwargs)
  TypeError: __init__() got an unexpected keyword argument 'gs_bucket'
* (May still be a problem in the storage extension but at least we can start ckan!)

ckanext/storage/__init__.py

@@ -24,8 +24,6 @@ def configure(self, config):
             if not k.startswith('ofs.') or k == 'ofs.impl':
                 continue
             kw[k[4:]] = v
-        from ckanext import storage
-        storage.ofs = get_impl(config.get('ofs.impl', 'google'))(**kw)
 
     def before_map(self, route_map):
         c = "ckanext.storage:StorageController"
@@ -53,8 +51,8 @@ def fix_stupid_pylons_encoding(data):
 class StorageController(BaseController):
     @property
     def ofs(self):
-        from ckanext import storage
-        return storage.ofs
+        ofs = get_impl(config.get('ofs.impl', 'google'))(**kw)
+        return ofs
 
     def set_metadata(self, bucket, label):
         if not label.startswith("/"): label = "/" + label