updated error message

Author: bekzod

src/ember-app.js

@@ -237,7 +237,7 @@ class EmberApp {
             // This is a failure mechanism so that node process doesn't get wedged if the `visit` never completes.
             timer = setTimeout(()=> {
               if (result._destroyAppInstance()) {
-                reject(new Error('App instance was forcefully destroyed in ' + destroyAppInstanceInMs + 'ms'));
+                reject(new Error('Fastboot forcefully destroyed App instance in ' + destroyAppInstanceInMs + 'ms'));
               }
             }, destroyAppInstanceInMs);
           }

test/fastboot-test.js

@@ -106,9 +106,9 @@ describe("FastBoot", function() {
       distPath: fixture('long-resolving-app')
     });
 
-    fastboot.visit('/', { destroyAppInstanceInMs: 300 })
+    fastboot.visit('/', { destroyAppInstanceInMs: 5 })
       .catch((e) => {
-        expect(e.message).to.equal('App instance was forcefully destroyed in 300ms');
+        expect(e.message).to.equal('Fastboot forcefully destroyed App instance in 5ms');
         done();
       });
   });