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_l3_rule.cpp b/src/vpp-api/vom/acl_l3_rule.cpp
index 4b96cae..417dc5f 100644
--- a/src/vpp-api/vom/acl_l3_rule.cpp
+++ b/src/vpp-api/vom/acl_l3_rule.cpp
@@ -147,7 +147,7 @@
   return m_priority;
 }
 
-action_t
+const action_t&
 l3_rule::action() const
 {
   return m_action;