[third_party] vendor argparse.

recipe_engine/test.py

Index: recipe_engine/test.py
diff --git a/recipe_engine/test.py b/recipe_engine/test.py
index 2924b206e684ff3b3738f9885ab45175148460fa..874712103c8433fe051f989a824340d3cec86cbf 100644
--- a/recipe_engine/test.py
+++ b/recipe_engine/test.py
@@ -4,7 +4,6 @@
 
 from __future__ import print_function
 
-import argparse
 import bdb
 import cStringIO
 import contextlib
@@ -36,6 +35,10 @@ from . import step_runner
 from . import stream
 from . import test_result_pb2
 
+from . import env
+
+import argparse  # this is vendored
+
 
 # These variables must be set in the dynamic scope of the functions in this
 # file.  We do this instead of passing because they're not picklable, and