reduced-complexity implementation of function to get rezzing object key

Signed-off-by: Melanie <melanie@t-data.com>

OpenSim/Region/ScriptEngine/Shared/Api/Interface/IOSSL_Api.cs

@@ -299,5 +299,11 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api.Interfaces
         /// <param name="b"></param>
         /// <returns></returns>
         LSL_Float osMax(double a, double b);
+
+        /// <summary>
+        /// Get the key of the object that rezzed this object.
+        /// </summary>
+        /// <returns>Rezzing object key or NULL_KEY if rezzed by agent or otherwise unknown.</returns>
+        LSL_Key osGetRezzingObject();
     }
 }