fixed calls in templates

Author: HugoMario

modules/swagger-codegen/src/main/resources/csharp-dotnet2/ApiClient.mustache

@@ -89,7 +89,7 @@ namespace {{clientPackage}}
 
             // add file parameter, if any
             foreach(var param in fileParams)
-                request.AddFile(param.Value.Name, param.Value.Writer, param.Value.FileName, param.Value.ContentType);
+                request.AddFile(param.Value.Name, param.Value.Writer, param.Value.FileName, param.Value.ContentLength, param.Value.ContentType);
 
             if (postBody != null) // http body (model) parameter
                 request.AddParameter("application/json", postBody, ParameterType.RequestBody);
@@ -116,7 +116,7 @@ namespace {{clientPackage}}
         /// <returns>Escaped string.</returns>
         public string EscapeString(string str)
         {
-            return RestSharp.Contrib.HttpUtility.UrlEncode(str);
+            return HttpUtility.UrlEncode(str);
         }
 
         /// <summary>