Skipping session create with JWT based auth

According to NSX Authentication team's response
in bug 2708018, we should not be using /api/session/create
with JWT based auth, which will cause
session create failed with 403 response.

Change-Id: Ic09090d633301401906815743bbdd83b55212203

vmware_nsxlib/v3/cluster.py

@@ -256,16 +256,10 @@ class NSXRequestsHTTPProvider(AbstractHTTPProvider):
                        'Content-Type': 'application/x-www-form-urlencoded'}
         # Insert the JWT in Auth header if using tokens for auth
         if token_provider:
-            try:
-                token_value = token_provider.get_token()
-                bearer_token = token_provider.get_header_value(token_value)
-                token_header = {"Authorization": bearer_token}
-                session.default_headers.update(token_header)
-                req_headers.update(token_header)
-            except exceptions.BadJSONWebTokenProviderRequest as e:
-                LOG.error("Session create failed for endpoint %s due to "
-                          "error in retrieving JSON Web Token: %s",
-                          provider.url, e)
+            # Don't call /api/session/create when using
+            # JWT Token Based Principal Identity auth scheme
+            LOG.debug("Skipping session create with JWT based auth")
+            return
         else:
             # With client certificate authentication, username and password
             # may not be provided.