Update 2015 test reference to follow LHCb!1020
Update to latest LHCbCond global tag for 2015: cond-20171211 (was cond20151016). Main change affecting Brunel is a fixed calorimeter calibration, LHCBCNDB-577
Update to latest LHCbCond global tag for 2015: cond-20171211 (was cond20151016). Main change affecting Brunel is a fixed calorimeter calibration, LHCBCNDB-577