Support to use SOAP 1.1 or 1.2.

example/soap_book_server/book_service.cc

@@ -21,7 +21,6 @@ bool BookService::Handle(const webcc::SoapRequest& soap_request,
                          webcc::SoapResponse* soap_response) {
   const std::string& operation = soap_request.operation();
 
-  soap_response->set_soapenv_ns(webcc::kSoapEnvNamespace);
   soap_response->set_service_ns({
     "ser",
     "http://www.example.com/book/"

example/soap_calc_client_parasoft/main.cc

@@ -7,8 +7,9 @@
 
 class CalcClient {
  public:
+  // NOTE: Parasoft's calculator service uses SOAP V1.1.
   CalcClient(const std::string& host, const std::string& port)
-      : soap_client_(host, port) {
+      : soap_client_(host, port, webcc::kSoapV11) {
     soap_client_.SetTimeout(5);
 
     soap_client_.set_url("/glue/calculator");

example/soap_calc_server/calc_service.cc

@@ -52,7 +52,6 @@ bool CalcService::Handle(const webcc::SoapRequest& soap_request,
 
   double result = calc(x, y);
 
-  soap_response->set_soapenv_ns(webcc::kSoapEnvNamespace);
   soap_response->set_service_ns({
     "cal",
     "http://www.example.com/calculator/"