lib/testutil/integration: increase StartRootMT timeout

This may help to address occasional flakiness that I observed when
running these tests locally.

Change-Id: Ibcc4a9dbe7367ebf51981f8fea965b3a9a3658d0
diff --git a/lib/testutil/integration/util.go b/lib/testutil/integration/util.go
index 6a6d9b8..fdc0afa 100644
--- a/lib/testutil/integration/util.go
+++ b/lib/testutil/integration/util.go
@@ -358,7 +358,7 @@
 	if err != nil {
 		return nil, "", err
 	}
-	s := expect.NewSession(nil, handle.Stdout(), time.Second)
+	s := expect.NewSession(nil, handle.Stdout(), 10*time.Second)
 	s.ExpectVar("PID")
 	if err := s.Error(); err != nil {
 		return nil, "", err