Fix logo at navbar

by run

~~~
$ find _includes -type f -exec sed -i "s/page.carpentry/site.carpentry/g" {} \;
$ find _layouts -type f -exec sed -i "s/page.carpentry/site.carpentry/g" {} \;
$ find _extras -type f -exec sed -i "s/page.carpentry/site.carpentry/g" {} \;
$ find _episodes -type f -exec sed -i "s/page.carpentry/site.carpentry/g" {} \;
$ find bin -type f -exec sed -i "s/page.carpentry/site.carpentry/g" {} \;
$ find assets -type f -exec sed -i "s/page.carpentry/site.carpentry/g" {} \;
~~~

Author: rgaiacs

_includes/navbar.html

@@ -12,15 +12,15 @@
       </button>
 
       {% comment %} Select what logo to display. {% endcomment %}
-      {% if page.carpentry == "swc" %}
+      {% if site.carpentry == "swc" %}
       <a href="{{ site.swc_site }}" class="pull-left">
         <img class="navbar-logo" src="{{ page.root }}/assets/img/swc-icon-blue.svg" alt="Software Carpentry logo" />
       </a>
-      {% elsif page.carpentry == "dc" %}
+      {% elsif site.carpentry == "dc" %}
       <a href="{{ site.dc_site }}" class="pull-left">
         <img class="navbar-logo" src="{{ page.root }}/assets/img/dc-icon-black.svg" alt="Data Carpentry logo" />
       </a>
-      {% elsif page.carpentry == "lc" %}
+      {% elsif site.carpentry == "lc" %}
       <a href="{{ site.lc_site }}" class="pull-left">
         <img class="navbar-logo" src="{{ page.root }}/assets/img/lc-icon-black.png" alt="Library Carpentry logo" />
       </a>