Related-Bug:#1446666 Added null checks in few ip validation function.
Related-Bug:#1446666
Added null checks in few ip validation function.

Change-Id: I14b271d4e7ba7bbbc65a097b6341db58f625e0dc

biswajit-mandal/contrail-web-core,biswajit-mandal/contrail-web-core,nagakiran/contrail-web-core,nagakiran/contrail-web-core,hari-sk/contrail-web-core,biswajit-mandal/contrail-web-core,hari-sk/contrail-web-core,hari-sk/contrail-web-core,vishnuvv/contrail-web-core,vishnuvv/contrail-web-core,nagakiran/contrail-web-core,vishnuvv/contrail-web-core