Fix test_request_no_token_dummy cms dependency.

* tests/test_auth_token_middleware.py: test_request_no_token_dummy has a
dependency on the keystone.common.cms module importing subprocess prior
to running. The cms._ensure_subprocess() function does this. Call this
function in the base test class's setUp method to ensure subprocess is
imported before symbols from that module are needed. Doing this in the
base setUp will ensure that this works for any additional tests with the
same dependency.

This fix is needed because testr runs tests in non deterministic order
which means that each test needs to be able to run on its own (eg in its
own process without any other tests running first) and they need to run
without interfering any other tests (each test must properly clean up
after itself). Prior to this commit test_request_no_token_dummy would
fail when executed on its own.

Closes-Bug: #1209300
Change-Id: I3cf669b94ed77ad0cd729ead0b4162a3f1b8819f

tests/test_auth_token_middleware.py

@@ -643,6 +643,12 @@ def setUp(self, expected_env=None, auth_version=None,
         self.fake_http = fake_http or FakeHTTPConnection
         self.set_middleware(self.fake_app, self.fake_http,
                             expected_env, self.conf)
+        # self.middleware.verify_signed_token will call
+        # _ensure_subprocess, but we need
+        # cms.subprocess.CalledProcessError to be imported first.
+        # Explicitly call _ensure_subprocess to make sure the import
+        # happens before we need it regardless of test order.
+        cms._ensure_subprocess()
 
         self.response_status = None
         self.response_headers = None