scons: Require python 2.7

less than 2.7 is not supported.

v2: - Remove check for python >= 2.0, since we've already enforced 2.7

Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
diff --git a/SConstruct b/SConstruct
index 6e034fb..51dc301 100644
--- a/SConstruct
+++ b/SConstruct
@@ -31,6 +31,7 @@
 # Minimal scons version
 
 EnsureSConsVersion(2, 4)
+EnsurePythonVersion(2, 7)
 
 
 #######################################################################