Start removing dependence on gflags.

Reviewed in https://codereview.appspot.com/7628044/.

This only removes the dependency from the core library, a second CL will
update all the samples.
diff --git a/tests/__init__.py b/tests/__init__.py
index 2451995..7913e6f 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -14,9 +14,8 @@
 
 __author__ = 'afshar@google.com (Ali Afshar)'
 
-import gflags
+import oauth2client.util
 
 def setup_package():
   """Run on testing package."""
-  FLAGS = gflags.FLAGS
-  FLAGS.positional_parameters_enforcement = 'EXCEPTION'
+  oauth2client.util.positional_parameters_enforcement = 'EXCEPTION'