[DM]: Configure local-as value if global asn is different

When mx bgp router is conifgured with 'local-autonomous-system',
DM should generate local-as conifguraion as follows.

protocols {
    bgp {
        group __contrail_external__ {
            type internal;
            neighbor 10.84.7.31 {
                peer-as 1000;
           }
        }

More details in the bug.

Change-Id: If2cfb53095a6af64fa7f05e1d98c07beed7f6d0c
Closes-Bug: #1549614
Closes-Bug: #1451972

src/config/device-manager/device_manager/db.py

@@ -560,8 +560,11 @@ def push_config(self):
                 peer = BgpRouterDM.get(peer_uuid)
                 if peer is None:
                     continue
-                external = (bgp_router.params['autonomous_system'] !=
-                            peer.params['autonomous_system'])
+                local_as = bgp_router.params.get('local_autonomous_system') or \
+                               bgp_router.params.get('autonomous_system')
+                peer_as = peer.params.get('local_autonomous_system') or \
+                               peer.params.get('autonomous_system')
+                external = (local_as != peer_as)
                 self.config_manager.add_bgp_peer(peer.params['address'],
                                                  peer.params, attr, external)
             self.config_manager.set_bgp_config(bgp_router.params)

src/config/device-manager/device_manager/physical_router_config.py

@@ -810,9 +810,8 @@ def _get_neighbor_config_xml(self, bgp_config, peers):
                         self._add_family_etree(nbr, session_attr)
                         self.add_bgp_auth_config(nbr, session_attr)
                         break
-            if params.get('autonomous_system') is not None:
-                etree.SubElement(
-                    nbr, "peer-as").text = str(params.get('autonomous_system'))
+            peer_as = params.get('local_autonomous_system') or params.get('autonomous_system')
+            etree.SubElement(nbr, "peer-as").text = str(peer_as)
     # end _get_neighbor_config_xml
 
     def send_bgp_config(self):
@@ -832,8 +831,8 @@ def send_bgp_config(self):
         etree.SubElement(
             routing_options_config,
             "route-distinguisher-id").text = self.bgp_params['identifier']
-        etree.SubElement(routing_options_config, "autonomous-system").text = \
-            str(self.bgp_params.get('autonomous_system'))
+        local_as = self.bgp_params.get('local_autonomous_system') or self.bgp_params.get('autonomous_system')
+        etree.SubElement(routing_options_config, "autonomous-system").text = str(local_as)
         config_list = [proto_config, routing_options_config]
         if self.ri_config is not None:
             config_list.append(self.ri_config)