messenger.tcp_transport: Reorder classes
messenger.tcp_transport: Reorder classes

This puts TCPConnection ahead of TCPTransport to fix a dependency problem
in a forthcoming commit.

MurphyMc/pox,pthien92/sdn,noxrepo/pox,noxrepo/pox,MurphyMc/pox,MurphyMc/pox,pthien92/sdn,pthien92/sdn,MurphyMc/pox,pthien92/sdn,noxrepo/pox,MurphyMc/pox,pthien92/sdn,noxrepo/pox