datatransfer: avoid mismatch family errors using RFC 6156

RFC 6156 propose to use REQUESTED-ADDRESS-FAMILY to be able to
communicate beetween a IPv6 network and a IPv4 network. Because
this parameter is negociated during the allocation we should use
two control channels to be able to communicate with all address
families.

Change-Id: Ie1659b20c4c7170697e4ad2949a519b0e87e35ae