Links to Admin+Dev guide now point to specific path

Reflects the change in filesystem structure from 1.2 where all docs were
stored in the same directory.

documentation.php

@@ -16,7 +16,7 @@
 
     <ul class="icons">
       <li>
-        <i class="icon-book"></i> <a href="<?php echo $g_docs_url, $t_doc_path; ?>">Administrator's Guide</a>
+        <i class="icon-book"></i> <a href="<?php echo $g_docs_url, $t_doc_path, $t_admin_guide; ?>">Administrator's Guide</a>
       </li>
       <li>
         <i class="icon-book"></i> <a href="<?php echo $g_wiki_url; ?>">Wiki</a>
@@ -65,7 +65,7 @@
           <i class="icon-book"></i> <a href="<?php echo $g_wiki_url; ?>doku.php/mantisbt:developers_corner">Developer's Corner</a>
         </li>
         <li>
-          <i class="icon-book"></i> <a href="<?php echo $g_docs_url, $t_doc_path; ?>">Developer's Guide</a>
+          <i class="icon-book"></i> <a href="<?php echo $g_docs_url, $t_doc_path, $t_dev_guide; ?>">Developer's Guide</a>
         </li>
         <li>
           <i class="icon-sitemap"></i> <a href="<?php echo $g_docs_url, $t_doc_path; ?>erd/latest.pdf">Entity-Relationship Diagram</a>