/: use local copy of ietflogo.gif instead of www.ietf.org (to avoid warnings about non-https content)

- Legacy-Id: 2103

ietf/templates/idrfc/main.html

@@ -49,7 +49,7 @@ td.ietf-main-intro { width:200px; background:#fff5df; padding:8px; border:1px so
 <table>
 <tr valign="middle">
 <td colspan="2" class="ietf-main-title"><h1>IETF Datatracker</h1></td>
-<td class="ietf-main-logo"><div><img src="http://www.ietf.org/images/ietflogo.gif" width="140" alt=""/></div></td>
+<td class="ietf-main-logo"><div><img src="/images/ietflogo.gif" width="140" alt=""/></div></td>
 </tr>
 
 <tr valign="top"><td class="ietf-main-search">