Comment 1 for bug 1425856

Though there was only one vgw in setup exporting 0/0 route, agent got a ecmp route for 0/0 route,
thought both next hop and label are same,there encap types differ.

<message from=\"<email address hidden>\" to=\"nodei5/bgp-peer\">
    <event xmlns=\"http://jabber.org/protocol/pubsub\">
        <items node=\"1/1/default-domain:admin:vgwvn:vgwvn\">
            <item id=\"0.0.0.0/0\">
                <entry>
                    <nlri>
                        <af>1</af>
                        <safi>1</safi>
                        <address>0.0.0.0/0</address>
                    </nlri>
                    <next-hops>
                        <next-hop>
                            <af>1</af>
                            <address>192.168.192.5</address>
                            <label>17</label>
                            <tunnel-encapsulation-list>
                                <tunnel-encapsulation>gre</tunnel-encapsulation>
                            </tunnel-encapsulation-list>
                        </next-hop>
                        <next-hop>
                            <af>1</af>
                            <address>192.168.192.5</address>
                            <label>17</label>
                            <tunnel-encapsulation-list>
                                <tunnel-encapsulation>gre</tunnel-encapsulation>
                                <tunnel-encapsulation>udp</tunnel-encapsulation>
                            </tunnel-encapsulation-list>
                        </next-hop>
                    </next-hops>
                    <version>1</version>
                    <virtual-network>default-domain:admin:vgwvn</virtual-network>
                    <sequence-number>0</sequence-number>
                    <security-group-list />
                    <local-preference>100</local-preference>
                </entry>
            </item>
        </items>

If there is a ecmp of vgw and traffic originates first from outside to contrail-domain VM,
agent was trying to get policy enabled next hop for reverse flow setup which would not
be created for vgw.
Fix for to take policy enabled next hop for reverse flow only destination is vm interface.