Fix perms when linking an object. Set root part perms to the perms

of the link set to make the build floater behave consistently.
Fixes permissions exploit introduced on 23 August.

OpenSim/Region/Framework/Scenes/SceneGraph.cs

@@ -1849,6 +1849,7 @@ namespace OpenSim.Region.Framework.Scenes
                         SceneObjectGroupsByLocalPartID[part.LocalId] = parentGroup;
                 }
 
+                parentGroup.AdjustChildPrimPermissions();
                 parentGroup.HasGroupChanged = true;
                 parentGroup.ProcessBackup(m_parentScene.SimulationDataService, true);
                 parentGroup.ScheduleGroupForFullUpdate();
@@ -1989,6 +1990,7 @@ namespace OpenSim.Region.Framework.Scenes
                     // return unless the root is deleted. This will remove them
                     // from the database. They will be rewritten immediately,
                     // minus the rows for the unlinked child prims.
+                    g.AdjustChildPrimPermissions();
                     m_parentScene.SimulationDataService.RemoveObject(g.UUID, m_parentScene.RegionInfo.RegionID);
                     g.TriggerScriptChangedEvent(Changed.LINK);
                     g.HasGroupChanged = true; // Persist