GBP V2

update the GBP plugin to implement the full NAT feature set of opflex agent

Change-Id: Ic06a039c889445ed0b9087fa1f292634192b0f8d
Signed-off-by: Neale Ranns <neale.ranns@cisco.com>
diff --git a/src/vpp-api/vom/acl_l2_rule.cpp b/src/vpp-api/vom/acl_l2_rule.cpp
index 1fb06e2..2b12e68 100644
--- a/src/vpp-api/vom/acl_l2_rule.cpp
+++ b/src/vpp-api/vom/acl_l2_rule.cpp
@@ -65,7 +65,7 @@
   return m_priority;
 }
 
-action_t
+const action_t&
 l2_rule::action() const
 {
   return m_action;