fix disks without placeholder

ereuse_devicehub/inventory/views.py

@@ -166,10 +166,14 @@ class DeviceDetailView(GenericMixin):
         )
 
         form_tags = TagDeviceForm(dhid=id)
+        placeholder = device.binding or device.placeholder
+        if not placeholder:
+            return NotFound()
+
         self.context.update(
             {
                 'device': device,
-                'placeholder': device.binding or device.placeholder,
+                'placeholder': placeholder,
                 'page_title': 'Device {}'.format(device.devicehub_id),
                 'form_tag_device': form_tags,
             }

ereuse_devicehub/templates/inventory/erasure_list.html

@@ -71,9 +71,13 @@
                                />
                       </td>
                       <td>
+                        {% if ac.device.phid() %}
                         <a href="{{ url_for('inventory.device_details', id=ac.device.dhid)}}">
                           {{ ac.device.serial_number.upper() }}
                         </a>
+                        {% else %}
+                        {{ ac.device.serial_number.upper() }}
+                        {% endif %}
                       </td>
                       <td>
                         <a href="{{ url_for('inventory.export', export_id='snapshot') }}?id={{ ac.snapshot.uuid }}">