VOM: logging, populate and stats fixes

logging: allow a client to register a callback handler to recieve log messages
         that way the client can maintain a correctly sequenced log
populate: fix the creation of interface and the setting of the handle
stats: the reset promise idea is not defined behaviour.
       Use an eanble/disable command pair

Change-Id: I347720bb65df2874c7619e722d593bc863ee2bf1
Signed-off-by: Neale Ranns <neale.ranns@cisco.com>
diff --git a/test/ext/vom_test.cpp b/test/ext/vom_test.cpp
index c9ae255..9176915 100644
--- a/test/ext/vom_test.cpp
+++ b/test/ext/vom_test.cpp
@@ -80,7 +80,7 @@
 class MockListener : public interface::event_listener,
                      public interface::stat_listener
 {
-    void handle_interface_stat(interface_cmds::stats_cmd *cmd)
+    void handle_interface_stat(interface_cmds::stats_enable_cmd *cmd)
     {
     }
     void handle_interface_event(interface_cmds::events_cmd *cmd)
@@ -1463,8 +1463,6 @@
 
     HW::enqueue(itf);
     HW::write();
-
-    HW::dequeue(itf);
 }
 
 BOOST_AUTO_TEST_CASE(test_interface_route_domain_change) {