adapt HLTControlFlowManager to range v3 0.11
fixes incompatibility with range v3 v0.11, see http://lhcb-nightlies.web.cern.ch/logs/build/nightly/lhcb-lcg-dev4/1592/x86_64-centos7-gcc9-opt/LHCb/#show_Hlt_HLTScheduler/Hlt_HLTScheduler_10
See LBCORE-2001
Edited by Gerhard Raven