Fix error handling in SecureSocket.initialize

tests/standalone/io/secure_socket_argument_test.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import "dart:io";
+
+void main() {
+  Expect.throws(() => SecureSocket.initialize(database: "foo.txt"));
+  Expect.throws(() => SecureSocket.initialize(password: false));
+  Expect.throws(() => SecureSocket.initialize(useBuiltinRoots: 7));
+  SecureSocket.initialize();
+}