CA-201728: Add new interface `has_vlan` and exception `Vlan_in_use`
CA-201728: Add new interface `has_vlan` and exception `Vlan_in_use`

Signed-off-by: sharad yadav <0ab5d8dd51ae0f2f9ed283cbbbb7a94d110e3347@citrix.com>

xapi-project/message-switch,xapi-project/message-switch,xapi-project/message-switch