Added return values for "Timeout" and "DNS" Errors

Added Return value for:
- WebExceptionStatus.NameResolutionFailure : "DNS lookup failed"
- case WebExceptionStatus.Timeout: "Connection timeout"

OpenRA.Game/Download.cs

@@ -28,7 +28,9 @@ namespace OpenRA
 			switch (ex.Status)
 			{
 				case WebExceptionStatus.NameResolutionFailure:
+					return "DNS lookup failed";
 				case WebExceptionStatus.Timeout:
+					return "Connection timeout";
 				case WebExceptionStatus.ConnectFailure:
 					return "Cannot connect to remote server";
 				case WebExceptionStatus.ProtocolError:
@@ -74,4 +76,4 @@ namespace OpenRA
 			cancelled = true;
 		}
 	}
-}
+}