Remove default rendering if sub-navigation

** Why are these changes being introduced:

* The standard page content template includes a conditional that will
  render a sub-navigation menu between the page title and the breadcrumb
  if no Table of Contents block is present in page. During testing so
  far, this feature has proved confusing; we've decided that it would
  be cleaner to remove this (at least for now) and recommend that site
  builders place a Table of Contents themselves if they want a duplicate
  navigation pathway (beyond what the main navigation will provide)

** Relevant ticket(s):

* https://mitlibraries.atlassian.net/browse/post-109

** How does this address that need:

* This removes the conditional within the page content template.

** Document any side effects to this change:

* None

Author: matt-bernhardt

view/omeka/site/page/show.phtml

@@ -16,12 +16,6 @@ if ($activePage) :
     <?php endif; ?>
 <?php endif; ?>
 
-<?php if ($activePage) : ?>
-    <?php if ($this->displayNavigation && $activePage['page']->hasPages()) : ?>
-    <nav class="sub-menu"><?php echo $nav->menu()->renderSubMenu(); ?></nav>
-    <?php endif; ?>
-<?php endif; ?>
-
 <?php $this->trigger('view.show.before'); ?>
 <div class="blocks">
     <?php echo $this->content; ?>