NullLinkProviders join network islands deterministically.

  - Added configuration parameters for order of instances.
  - got rid of 'flicker' flag since it's redundant.

Reference: ONOS-890

Change-Id: I0217e17f2a55d85e0a1fc8f2b3ea8cb54cb87517
diff --git a/tools/package/etc/org.onosproject.provider.nil.link.impl.NullLinkProvider.cfg b/tools/package/etc/org.onosproject.provider.nil.link.impl.NullLinkProvider.cfg
index cc7e7aa..afc3fd9 100644
--- a/tools/package/etc/org.onosproject.provider.nil.link.impl.NullLinkProvider.cfg
+++ b/tools/package/etc/org.onosproject.provider.nil.link.impl.NullLinkProvider.cfg
@@ -1,13 +1,12 @@
 # Sample configurations for the NullLinkProvider.
 
 #
-# If enabled, generates LinkDetected and LinkVanished events
-# to make the link appear to be flapping.
-#
-# flicker = true
-
-#
 # If enabled, sets the time between LinkEvent generation,
 # in milliseconds.
 #
 # eventRate = 2000
+
+#
+# Set order of islands to chain together, in a line.
+#
+neighbors = 192.168.56.20,192.168.56.30,192.168.56.40