hard coded Tree name in LowRecoilFunctions.h

[hschellman]

calculators/LowRecoilFunctions.h: return GetDouble("MasterAnaDev_recoil_E");

Generally you should not hardcode the tree name but instead use

std::string(MinervaUniverse::GetTreeName()+"_recoil_E")

Can the owner look at this?

[ryounsumiko]

Fixed by commit 39fd6f9