don't hide depth 2 when local toc tree

sass/_theme_layout.sass

@@ -73,6 +73,9 @@
   li ul
     margin-bottom: 0
     display: none
+  .local-toc
+    li ul
+      display: block
   li ul li a
     margin-bottom: 0
     color: $text-light

sphinx_rtd_theme/layout.html

@@ -104,11 +104,11 @@
         {% set toctree = toctree(maxdepth=2, collapse=False) %}
         {% if not next and not prev %}
             <!-- Local TOC for single page -->
-            {{ toc }}
+            <div class="local-toc">{{ toc }}</div>
         {% elif toctree %}
             {{ toctree }}
         {% else %}
-            {{ toc }}
+          <div class="local-toc">{{ toc }}</div>
         {% endif %}
       </div>
       &nbsp;