Move userId to post data

MediaBrowser.Api/HttpHandlers/UserAuthenticationHandler.cs

@@ -12,7 +12,7 @@ namespace MediaBrowser.Api.HttpHandlers
     {
         protected override async Task<AuthenticationResult> GetObjectToSerialize()
         {
-            Guid userId = Guid.Parse(QueryString["userid"]);
+            Guid userId = Guid.Parse(await GetFormValue("userId").ConfigureAwait(false));
             User user = Kernel.Instance.Users.First(u => u.Id == userId);
 
             string password = await GetFormValue("password").ConfigureAwait(false);

MediaBrowser.ApiInteraction/ApiClient.cs

@@ -657,7 +657,9 @@ namespace MediaBrowser.ApiInteraction
             string url = ApiUrl + "/UserAuthentication?userId=" + userId;
             url += "&dataformat=" + SerializationFormat.ToString();
 
-            HttpContent content = new StringContent("password=" + password, Encoding.UTF8, "application/x-www-form-urlencoded");
+            string postContent = string.Format("userid={0}&password={1}", userId, password);
+
+            HttpContent content = new StringContent(postContent, Encoding.UTF8, "application/x-www-form-urlencoded");
 
             HttpResponseMessage msg = await HttpClient.PostAsync(url, content).ConfigureAwait(false);