vcl: use want_tx_evt for ct sessions
vcl: use want_tx_evt for ct sessions

Change-Id: Id46c651c41b1c633326081583ee3383e27ef475d
Signed-off-by: Florin Coras <c9715e5cdf0718c2e9b10678757dfb027875eba2@cisco.com>

chrisy/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,vpp-dev/vpp,chrisy/vpp,FDio/vpp,vpp-dev/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp,vpp-dev/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp,vpp-dev/vpp,vpp-dev/vpp