SceneShapeSubSceneOverride: Remove SceneInterface visibility check

In df78cb8 changes were made to the
`LiveScene` implementation so that we take into account visibility
overrides higher up the hierarchy. This makes the changes introduced
in 07b40ee obsolete. In fact a
`scene:visibility` value stored in the cache stomps over the
visibility determination done by `LiveScene`.

Author: yannci

src/IECoreMaya/SceneShapeSubSceneOverride.cpp

@@ -1418,16 +1418,6 @@ void SceneShapeSubSceneOverride::visitSceneLocations( const SceneInterface *scen
 		return;
 	}
 
-	// respect visibility attribute
-	if( sceneInterface->hasAttribute( SceneInterface::visibilityName ) )
-	{
-		ConstBoolDataPtr vis = runTimeCast<const BoolData>( sceneInterface->readAttribute( SceneInterface::visibilityName, m_time ) );
-		if( vis && !vis->readable() )
-		{
-			return;
-		}
-	}
-
 	MMatrix accumulatedMatrix;
 	if( !isRoot )
 	{