Fix session clearing in the test helper.

LogSubscriberTest ends up using the LogSubscripter::TestHelper which
prevents the normal test helper from running, so the session must be
cleared there as well.

test/detailed_log_subscriber_test.rb

@@ -9,6 +9,7 @@ def setup
     @page = { :page => { :id => 1, :title => 'Shopify API' } }.to_json
     @ua_header = "\"User-Agent\"=>\"ShopifyAPI/#{ShopifyAPI::VERSION} ActiveResource/#{ActiveResource::VERSION::STRING} Ruby/#{RUBY_VERSION}\""
 
+    ShopifyAPI::Base.clear_session
     ShopifyAPI::Base.site = "http://localhost/admin"
 
     ActiveResource::LogSubscriber.attach_to :active_resource

test/test_helper.rb

@@ -34,6 +34,7 @@ def setup
       end
     end
 
+    ShopifyAPI::Base.clear_session
     ShopifyAPI::Base.site = "http://localhost/admin"
     ShopifyAPI::Base.password = nil
     ShopifyAPI::Base.user = nil