Fix DownloadStation integration in DSM 7

(cherry picked from commit b0753ab153a79203de10a928e99fcec5b6a7c895)

src/NzbDrone.Core/Download/Clients/DownloadStation/Proxies/DiskStationProxyBase.cs

@@ -131,7 +131,7 @@ namespace NzbDrone.Core.Download.Clients.DownloadStation.Proxies
         {
             var authInfo = GetApiInfo(DiskStationApi.Auth, settings);
 
-            var requestBuilder = BuildRequest(settings, authInfo, "login", 2);
+            var requestBuilder = BuildRequest(settings, authInfo, "login", authInfo.MaxVersion >= 7 ? 6 : 2);
             requestBuilder.AddQueryParam("account", settings.Username);
             requestBuilder.AddQueryParam("passwd", settings.Password);
             requestBuilder.AddQueryParam("format", "sid");