Observation_lib: fix scan service errors

process/Observation_lib/process.js

@@ -566,10 +566,11 @@ Observation.getEntityFilter = function (pEntity, pFilter)
             "childs":[]
         }
     
-    return JSON.stringify({
-        "filter":pFilter,
-        "entity":pEntity
-    });
+    var res = {
+            "filter":pFilter,
+            "entity":pEntity
+        };
+    return JSON.stringify(res);
 }
 
 /**