Update oper data when dhcp options in IPAM are modified.
Update oper data when dhcp options in IPAM are modified.

Change-Id: I4306529bc6d3aec190a6fb417d6848ffac9f1d3b
closes-bug: #1610083
(cherry picked from commit 9d612f7b696614e22f88c356356d5f4298039221)

tcpcloud/contrail-controller,tcpcloud/contrail-controller,tcpcloud/contrail-controller,tcpcloud/contrail-controller,tcpcloud/contrail-controller,tcpcloud/contrail-controller