[doc] Fix: Tutorial: Building a Dashboard

The directory structure after executing the commands is
different from the document provided.
This patch make it consistent.

Change-Id: I5a78765c4760d3bc0b27a0f67f2d47960fd4824d

doc/source/contributor/tutorials/dashboard.rst

@@ -71,8 +71,8 @@ structure that looks like the following::
     │   └── views.py
     ├── static
     │   └── mydashboard
-    │       ├── css
-    │       │   └── mydashboard.css
+    │       ├── scss
+    │       │   └── mydashboard.scss
     │       └── js
     │           └── mydashboard.js
     └── templates
@@ -134,7 +134,6 @@ As described above, the ``mypanel`` directory under
 
    mypanel
     ├── __init__.py
-    ├── models.py
     ├── panel.py
     ├── templates
     │   └── mypanel