Bug 1059847: Show 'Log not found error' instead of 'loading' when the log is no longer available

deferred is not initialized here, so you can either initialize it out of the 
```javascript
if(found){
```
condition or use 
```javascript
return $q.reject(reason);
```
Also, deferred.reject doesn't return a promise, so you may want to return deferred.promise after you reject it