Use real sysname in hyperlink to ipdevinfo

This fixes a small bug in the default configuration of
etc/geomap/popup_place.html

Because:
- Geomap may internally have shortened box.sysname by chopping off the
  DOMAIN_SUFFIX.
- Using a shortened sysname will not produce a valid ipdevinfo link.
- Geomap stores the original sysname in the box.real_sysname property.

Fixes #2239

python/nav/etc/geomap/popup_place.html

@@ -36,7 +36,7 @@
             {% for box in room.netboxes %}
               <li>
                 <h5>
-                  <a href="{% url 'ipdevinfo-details-by-name' box.sysname %}"
+                  <a href="{% url 'ipdevinfo-details-by-name' box.real_sysname %}"
                      target="_blank"
                      title="View in IP Device Info">{{ box.sysname }}</a>
                 </h5>