Don't attempt to retrieve session without session id
Don't attempt to retrieve session without session id

Retrieving session by nil successfully returns nil from
InMemorySessionStore, but when using AR model, Shop.find(nil) fails.

No need to lookup nil in the first place.

egowens/shopify_app,nwallace/shopify_app,icodedev7/development,kewaunited/shopify_app,egowens/shopify_app,icodedev7/development,egowens/shopify_app,kewaunited/shopify_app,Shopify/shopify_app,mig1098/shopify_app,Shopify/shopify_app,Shopify/shopify_app,Shopify/shopify_app,nwallace/shopify_app,mig1098/shopify_app