support user agent

Signed-off-by: gaort <rutong.grt@alibaba-inc.com>

sdk/client.go

@@ -190,6 +190,9 @@ func (client *Client) DoActionWithSigner(request requests.AcsRequest, response r
 		finalSigner = client.signer
 	}
 	httpRequest, err := buildHttpRequest(request, finalSigner, regionId)
+	if client.config.UserAgent != "" {
+		httpRequest.Header.Set("User-Agent", client.config.UserAgent)
+	}
 	if err != nil {
 		return
 	}

sdk/requests/acs_reqeust.go

@@ -95,8 +95,9 @@ type baseRequest struct {
 	Port     string
 	RegionId string
 
-	product    string
-	version    string
+	product string
+	version string
+
 	actionName string
 
 	AcceptFormat string