Make sure the debug_stub test only runs when a sufficient python version is found.
Make sure the debug_stub test only runs when a sufficient python version is
found.

BUG=http://code.google.com/p/nativeclient/issues/detail?id=1724
TEST=trybots
Review URL: http://codereview.chromium.org/6883153

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@5029 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

nacl-webkit/native_client,sbc100/native_client,sbc100/native_client,nacl-webkit/native_client,nacl-webkit/native_client,sbc100/native_client,nacl-webkit/native_client,nacl-webkit/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client