Improve commenting in the test code

Change-Id: I407d3293524203385153ac9094753cffe9ef1772
diff --git a/drivers/NetgearXSM.py b/drivers/NetgearXSM.py
index 3a49f1f..285f438 100644
--- a/drivers/NetgearXSM.py
+++ b/drivers/NetgearXSM.py
@@ -776,7 +776,8 @@
     buf = p.port_get_trunk_vlan_list("1/0/9")
     p.dump_list(buf)
     
-    # The adds below are NOOPs in effect on this switch
+    # The adds below are NOOPs in effect on this switch - no filtering
+    # for "trunk" ports
     print "Add 1/0/9 to VLAN 2"
     p.port_add_trunk_to_vlan("1/0/9", 2)
     print "Add 1/0/9 to VLAN 3"
@@ -787,6 +788,7 @@
     buf = p.port_get_trunk_vlan_list("1/0/9")
     p.dump_list(buf)
 
+    # And the same for removals here
     p.port_remove_trunk_from_vlan("1/0/9", 3)
     p.port_remove_trunk_from_vlan("1/0/9", 3)
     p.port_remove_trunk_from_vlan("1/0/9", 4)