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: http://src.chromium.org/svn/trunk/src/net/tools/testserver@284431 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
diff --git a/testserver.py b/testserver.py
index 83920d8..0ff4e69 100755
--- a/testserver.py
+++ b/testserver.py
@@ -2011,6 +2011,7 @@
         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(