slapos_cloud: Set proxy roles for allow invoke it by the allocator.

master/bt5/slapos_cloud/SkinTemplateItem/portal_skins/slapos_cloud/Computer_checkAndUpdateCapacityScope.py

 import json
 computer = context
 portal = context.getPortalObject()
+from zExceptions import Unauthorized
+if REQUEST is not None:
+  raise Unauthorized
 
 if computer.getAllocationScope() not in ['open/public', 'open/subscription']:
   # Don't update non public computer

master/bt5/slapos_cloud/SkinTemplateItem/portal_skins/slapos_cloud/Computer_checkAndUpdateCapacityScope.xml

@@ -50,7 +50,15 @@
         </item>
         <item>
             <key> <string>_params</string> </key>
-            <value> <string>allocated_instance=None</string> </value>
+            <value> <string>allocated_instance=None, REQUEST=None</string> </value>
+        </item>
+        <item>
+            <key> <string>_proxy_roles</string> </key>
+            <value>
+              <tuple>
+                <string>Manager</string>
+              </tuple>
+            </value>
         </item>
         <item>
             <key> <string>id</string> </key>