* Dont fetch mac address if interface is NULL Closes-bug:#1599247
* Dont fetch mac address if interface is NULL
Closes-bug:#1599247

Change-Id: I2845db66aaa447ee4902c8607aab5c242d6bacab

rombie/contrail-controller,rombie/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,nischalsheth/contrail-controller,nischalsheth/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,codilime/contrail-controller,eonpatapon/contrail-controller,codilime/contrail-controller,nischalsheth/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,codilime/contrail-controller,codilime/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,nischalsheth/contrail-controller,codilime/contrail-controller,nischalsheth/contrail-controller,codilime/contrail-controller,rombie/contrail-controller