container: increase copy timeout

The implementation of this involves file IO and running an external
process, so it can take some time on a system under heavy load.

internal/virter/docker.go

@@ -108,7 +108,7 @@ func containerRun(ctx context.Context, containerProvider containerapi.ContainerP
 	// container. In these cases, the container itself is still valid.
 	if copyStep != nil {
 		// Use a fresh Context here because ctx may have been canceled
-		copyCtx, copyCancel := context.WithTimeout(context.Background(), 5*time.Second)
+		copyCtx, copyCancel := context.WithTimeout(context.Background(), 20*time.Second)
 		defer copyCancel()
 		err = containerCopy(copyCtx, containerProvider, containerID, copyStep)
 		if err != nil {