Correctly trigger auth request when no user was specified and no

anonymous user is registered

Author: alexrobin

sensorhub-core/src/main/java/org/sensorhub/impl/module/ModuleSecurity.java

@@ -105,10 +105,8 @@ public void setCurrentUser(String userID)
 
         // lookup user info 
         IUserInfo user = SensorHub.getInstance().getSecurityManager().getUserInfo(userID);
-        if (user == null)
-            throw new AccessControlException("Permission denied: Unknown user " + userID);
-        
-        currentUser.set(user);
+        if (user != null)        
+            currentUser.set(user);
     }