Don't run example for old pythons

Examples/python/import_packages/namespace_pkg/Makefile

@@ -1,5 +1,4 @@
 TOP        = ../../..
-PY3        = 1
 SWIGEXE    = $(TOP)/../swig
 SWIG_LIB_DIR = $(TOP)/../$(TOP_BUILDDIR_TO_TOP_SRCDIR)Lib
 SRCS       = robin.c
@@ -7,11 +6,10 @@ TARGET     = robin
 INTERFACE  = robin.i
 
 check: build
-	$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' PY3='$(PY3)' python_run
+	$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' python_run
 
 build:
 	$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' SRCS='$(SRCS)' \
-        PY3='$(PY3)' \
 	SWIG_LIB_DIR='$(SWIG_LIB_DIR)' SWIGEXE='$(SWIGEXE)' \
 	TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' python
 

Examples/python/import_packages/namespace_pkg/runme.py

@@ -1,5 +1,10 @@
 import os, sys, setupPkg
 
+# These examples rely on namespace packages.  Don't
+# run them for old python interpreters.
+if sys.version_info < (3, 3, 0):
+    sys.exit(0)
+
 setupPkg.copyMods()
 
 # Run each test with a seperate interpreter