Return 400 for invalid parent type
Return 400 for invalid parent type

Added check for validity of parent type and return 400.
Closes-Bug: 1621129

Change-Id: I1047f900a8a3651753638572064caed8ccfabaf3

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