Don't inspect oslo.context

When creating an oslo.context we inspected the __init__ string to figure
out if roles were part of the context. This was added in oslo.context
2.2 and there needed to be compatibility between old and new.

Now that requirements specify oslo.context >= 2.9 we don't need this
clause any more, and it is causing release issues with older versions of
positional.

Remove the inspection and rely on newer versions of oslo.context.

Closes-Bug: #1620963
Change-Id: I2fcb4f1718ae5e5b50e26d9dee0e0df2f1e6cf72

barbican/context.py

@@ -13,7 +13,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import inspect
 import oslo_context
 from oslo_policy import policy
 
@@ -29,23 +28,12 @@ class RequestContext(oslo_context.context.RequestContext):
     accesses the system, as well as additional request information.
     """
 
-    def __init__(self, roles=None, policy_enforcer=None, project=None,
-                 **kwargs):
+    def __init__(self, policy_enforcer=None, project=None, **kwargs):
         # prefer usage of 'project' instead of 'tenant'
         if project:
             kwargs['tenant'] = project
         self.project = project
         self.policy_enforcer = policy_enforcer or policy.Enforcer(CONF)
-
-        # NOTE(edtubill): oslo_context 2.2.0 now has a roles attribute in
-        # the RequestContext. This will make sure of backwards compatibility
-        # with past oslo_context versions.
-        argspec = inspect.getargspec(super(RequestContext, self).__init__)
-        if 'roles' in argspec.args:
-            kwargs['roles'] = roles
-        else:
-            self.roles = roles or []
-
         super(RequestContext, self).__init__(**kwargs)
 
     def to_dict(self):