Set external route target only on first service RI for left and last service RI for right network.
Set external route target only on first service RI for left and last service RI for right network.

Change-Id: I89046353892b34d93bbd56d068eca919e9291a7e
Closes-Bug: 1436642

facetothefate/contrail-controller,reiaaoyama/contrail-controller,nischalsheth/contrail-controller,vpramo/contrail-controller,rombie/contrail-controller,facetothefate/contrail-controller,reiaaoyama/contrail-controller,tcpcloud/contrail-controller,tcpcloud/contrail-controller,hthompson6/contrail-controller,sajuptpm/contrail-controller,sajuptpm/contrail-controller,numansiddique/contrail-controller,tcpcloud/contrail-controller,hthompson6/contrail-controller,reiaaoyama/contrail-controller,sajuptpm/contrail-controller,numansiddique/contrail-controller,nischalsheth/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,facetothefate/contrail-controller,tcpcloud/contrail-controller,hthompson6/contrail-controller,nischalsheth/contrail-controller,codilime/contrail-controller,hthompson6/contrail-controller,rombie/contrail-controller,vmahuli/contrail-controller,codilime/contrail-controller,eonpatapon/contrail-controller,DreamLab/contrail-controller,vpramo/contrail-controller,nischalsheth/contrail-controller,nischalsheth/contrail-controller,nischalsheth/contrail-controller,reiaaoyama/contrail-controller,nischalsheth/contrail-controller,numansiddique/contrail-controller,sajuptpm/contrail-controller,DreamLab/contrail-controller,codilime/contrail-controller,numansiddique/contrail-controller,vpramo/contrail-controller,rombie/contrail-controller,vpramo/contrail-controller,facetothefate/contrail-controller,codilime/contrail-controller,vpramo/contrail-controller,vmahuli/contrail-controller,hthompson6/contrail-controller,DreamLab/contrail-controller,eonpatapon/contrail-controller,vmahuli/contrail-controller,tcpcloud/contrail-controller,eonpatapon/contrail-controller,codilime/contrail-controller,sajuptpm/contrail-controller,codilime/contrail-controller,tcpcloud/contrail-controller,vmahuli/contrail-controller,rombie/contrail-controller,sajuptpm/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,eonpatapon/contrail-controller,DreamLab/contrail-controller,DreamLab/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,facetothefate/contrail-controller,numansiddique/contrail-controller,reiaaoyama/contrail-controller,vmahuli/contrail-controller