Remove use of positional decorator

The positional decorator results in poorly maintainable code in
a misguided effort to emulate python3's key-word-arg only notation
and functionality. This patch removes oslo.context dependance
on the positional decorator.

Change-Id: I9b83917fedd00a8d4fdf904208a17ebdc5cda59a

oslo_context/context.py

@@ -33,7 +33,6 @@ import uuid
 import warnings
 
 import debtcollector
-from positional import positional
 
 _request_store = threading.local()
 
@@ -179,7 +178,6 @@ class RequestContext(object):
 
     user_idt_format = u'{user} {tenant} {domain} {user_domain} {p_domain}'
 
-    @positional(enforcement=positional.WARN)
     def __init__(self,
                  auth_token=None,
                  user=None,

oslo_context/tests/test_context.py

@@ -562,13 +562,6 @@ class ContextTest(test_base.BaseTestCase):
                           'service_roles': service_roles},
                          ctx.to_policy_values())
 
-    def test_positional_args(self):
-        context.RequestContext('abc', 'def')
-
-        self.assertEqual(1, len(self.warnings.log))
-        self.assertIn('__init__ takes at most 1 positional',
-                      str(self.warnings.log[0].message))
-
     def test_policy_deprecations(self):
         user = uuid.uuid4().hex
         user_domain = uuid.uuid4().hex

requirements.txt

@@ -5,4 +5,3 @@
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
 
 debtcollector>=1.2.0 # Apache-2.0
-positional>=1.1.1 # Apache-2.0