[3336] Renew and Rebind timers optional in the config example for DHCPv4.

doc/examples/kea4/single-subnet.json

@@ -21,8 +21,12 @@
 # to start REBIND procedure (emergency renewal that allows switching
 # to a different server).
   "valid-lifetime": 4000,
-  "renew-timer": 1000,
-  "rebind-timer": 2000,
+
+# Renew and rebind timers are commented out. This implies that options
+# 58 and 59 will not be sent to the client. Uncomment them to send
+# these options.
+#  "renew-timer": 1000,
+#  "rebind-timer": 2000,
 
 # The following list defines subnets. We have only one subnet
 # here.