[wol] Add a 1 second sleep between WoL packets

WoL is still flakey even when sending it repeatedly, this attempts to
spread the packets out to see if that resolves the issue.

Bug: IN-571
Change-Id: I78678b0b8cff3b203d5f7d6b19e28dde05215ae1
diff --git a/pdu/wol/wol.go b/pdu/wol/wol.go
index 2b78d82..f05d503 100644
--- a/pdu/wol/wol.go
+++ b/pdu/wol/wol.go
@@ -9,6 +9,7 @@
 	"fmt"
 	"net"
 	"regexp"
+	"time"
 )
 
 var (
@@ -99,6 +100,7 @@
 		if err != nil {
 			return err
 		}
+		time.Sleep(1 * time.Second)
 	}
 
 	return nil