slapos_cloud: really check source/destination_project...

master/bt5/slapos_cloud/PropertySheetTemplateItem/portal_property_sheets/SlapOSVirtualMasterSourceProjectConstraint/source_or_destination_project_constraint_constraint.xml

@@ -26,7 +26,7 @@
         </item>
         <item>
             <key> <string>expression</string> </key>
-            <value> <string>python: len([x for x in [here.getSourceSectionValue(portal_type=\'Project\'), here.getDestinationSectionValue(portal_type=\'Project\')] if ((x is not None) and (x.getValidationState() in (\'validated\', \'invalidated\', \'suspended\')))]) != 0</string> </value>
+            <value> <string>python: len([x for x in [here.getSourceProjectValue(portal_type=\'Project\'), here.getDestinationProjectValue(portal_type=\'Project\')] if ((x is not None) and (x.getValidationState() in (\'validated\', \'invalidated\', \'suspended\')))]) != 0</string> </value>
         </item>
         <item>
             <key> <string>id</string> </key>
@@ -34,7 +34,7 @@
         </item>
         <item>
             <key> <string>message_expression_false</string> </key>
-            <value> <string>source_project or destination_project is required</string> </value>
+            <value> <string>A project is required</string> </value>
         </item>
         <item>
             <key> <string>portal_type</string> </key>