Fixed incorrectly set site url, if given

material/partials/header.html

@@ -3,11 +3,11 @@
     <div class="md-flex">
       <div class="md-flex__cell md-flex__cell--shrink">
         {% if config.extra.logo %}
-          <a href="{{ nav.homepage.url }}" title="{{ config.site_name }}" class="md-logo md-header-nav__button">
+          <a href="{{ config.site_url | default(nav.homepage.url, true) }}" title="{{ config.site_name }}" class="md-logo md-header-nav__button">
             <img src="{{ base_url }}/{{ config.extra.logo }}" width="24" height="24">
           </a>
         {% else %}
-          <a href="{{ nav.homepage.url }}" title="{{ config.site_name }}" class="md-icon md-icon--home md-header-nav__button">
+          <a href="{{ config.site_url | default(nav.homepage.url, true) }}" title="{{ config.site_name }}" class="md-icon md-icon--home md-header-nav__button">
           </a>
         {% endif %}
       </div>

src/partials/header.html

@@ -30,13 +30,15 @@
       <!-- Link to home -->
       <div class="md-flex__cell md-flex__cell--shrink">
         {% if config.extra.logo %}
-          <a href="{{ nav.homepage.url }}" title="{{ config.site_name }}"
+          <a href="{{ config.site_url | default(nav.homepage.url, true) }}"
+              title="{{ config.site_name }}"
               class="md-logo md-header-nav__button">
             <img src="{{ base_url }}/{{ config.extra.logo }}"
                 width="24" height="24" />
           </a>
         {% else %}
-          <a href="{{ nav.homepage.url }}" title="{{ config.site_name }}"
+          <a href="{{ config.site_url | default(nav.homepage.url, true) }}"
+              title="{{ config.site_name }}"
               class="md-icon md-icon--home md-header-nav__button">
           </a>
         {% endif %}