Fixed: (Indexers) Download requests not using the configured proxy

Fixes #520

src/NzbDrone.Core/Indexers/TorrentIndexerBase.cs

@@ -43,7 +43,7 @@ namespace NzbDrone.Core.Indexers
 
             try
             {
-                var response = await _httpClient.ExecuteAsync(request);
+                var response = await _httpClient.ExecuteAsync(request, Definition);
                 torrentData = response.ResponseData;
             }
             catch (HttpException ex)

src/NzbDrone.Core/Indexers/UsenetIndexerBase.cs

@@ -39,7 +39,7 @@ namespace NzbDrone.Core.Indexers
 
             try
             {
-                var response = await _httpClient.ExecuteAsync(request);
+                var response = await _httpClient.ExecuteAsync(request, Definition);
                 nzbData = response.ResponseData;
 
                 _logger.Debug("Downloaded nzb for release finished ({0} bytes from {1})", nzbData.Length, link.AbsoluteUri);