veyron/services/mgmt/device/impl: Increase some timeouts

IPC latency has gone up due to some recent security-related change. This change
is an attempt at making the device impl test not time out when run with --race

Change-Id: I704e559465c7e6e072f1e9dc392c4f9d29db49b4
diff --git a/services/mgmt/device/impl/impl_test.go b/services/mgmt/device/impl/impl_test.go
index 1113c34..84a5f69 100644
--- a/services/mgmt/device/impl/impl_test.go
+++ b/services/mgmt/device/impl/impl_test.go
@@ -504,7 +504,7 @@
 type pingServer chan<- string
 
 // TODO(caprita): Set the timeout in a more principled manner.
-const pingTimeout = 20 * time.Second
+const pingTimeout = 60 * time.Second
 
 func (p pingServer) Ping(_ ipc.ServerContext, arg string) {
 	p <- arg