6630878: clean target in sun/xawt is incomplete

Summary: clean target should remove .gen_icons
Reviewed-by: yan

jdk/make/sun/xawt/Makefile

 #
-# Copyright 2002-2007 Sun Microsystems, Inc.  All Rights Reserved.
+# Copyright 2002-2008 Sun Microsystems, Inc.  All Rights Reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # This code is free software; you can redistribute it and/or modify it
@@ -260,6 +260,7 @@ generated.clean:
 	$(RM) -r $(WRAPPER_GENERATOR_TEMPDIR)
 	$(RM) -r $(WRAPPER_GENERATOR_DIR)
 	$(RM) -r $(GEN_DIR)/*.java
+	$(RM) -r $(TEMPDIR)/.gen_icons
 
 ifdef OPENJDK
     ICONS_PATH_PREFIX=$(PLATFORM_SRC)