add error normalization

- as part of balderdashy/waterline-adapter-tests#89

lib/connections/spawn.js

@@ -88,6 +88,12 @@ module.exports = function spawnConnection (connectionObject, fn, cb__spawnConnec
 
         // Release the connection, then pass control back to Waterline core.
         connectionObject.connection.releaseConnection(liveConnection, function sendBackError ( /* thisErrDoesntMatter */ ) {
+
+          // Normalize the errors a bit. There could be a formattedErr if we inspect
+          // and augment the error. But to ensure compatibility with other adapters attach an
+          // originalError key to th error.
+          err.originalError = err;
+
           cb__spawnConnection(err);
         });
         return;