Set tls_client_cert_optional in net/.../testserver.py.

Before this value wasn't set at all leading to crashes of the test server if tsls_client_auth was enabled.

BUG=NONE
TBR=rsleevi@chromium.org

Review URL: https://codereview.chromium.org/407653005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284431 0039d316-1c4b-4281-b951-d872f2087c98

net/tools/testserver/testserver.py

@@ -2011,6 +2011,7 @@ class ServerRunner(testserver_base.TestServerRunner):
         websocket_options.private_key = self.options.cert_and_key_file
         websocket_options.certificate = self.options.cert_and_key_file
       if self.options.ssl_client_auth:
+        websocket_options.tls_client_cert_optional = False
         websocket_options.tls_client_auth = True
         if len(self.options.ssl_client_ca) != 1:
           raise testserver_base.OptionError(