[INTERNAL] restored transport mode selection

This behavior was disabled due to a move of the network layer to the
Saros core. This patch restores the functionality again.

Change-Id: I86445d0f2f0182dc3399f3fbd067f44379f37dbc
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1371
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>