fixed a couple bugs found in the workflow examples

oauth3.core.js

@@ -708,6 +708,7 @@
           return OAUTH3.PromiseA.reject(OAUTH3.error.parse(directives.issuer /*providerUri*/, params));
         }
 
+        OAUTH3.hooks.session._cache = {};
         return params;
       });
     }

oauth3.issuer.mock.js

@@ -177,12 +177,12 @@
   };
 
   OAUTH3.authz.scopes = function () {
-    return {
+    return OAUTH3.PromiseA.resolve({
       pending: ['oauth3_authn']   // not yet accepted
     , granted: []                 // all granted, ever
     , requested: ['oauth3_authn'] // all requested, now
     , accepted: []                // granted (ever) and requested (now)
-    };
+    });
   };
   OAUTH3.authz.grants = function (providerUri, opts) {
     if ('POST' === opts.method) {