CaloTools - Fix trivial TMVA leaks
addresses numerous sanitizer leaks such as
Direct leak of 640 byte(s) in 4 object(s) allocated from:
#0 0x7f31c58d9236 in operator new[](unsigned long) ../../../../gcc-7.3.0/libsanitizer/lsan/lsan_interceptors.cc:164
#1 0x7f3122b25890 in ReadMLPMiddle::Initialize() /workspace/build/REC/REC_HEAD/Calo/CaloTools/src/TMV_MLP_middle.C:264
#2 0x7f3122b25890 in std::_MakeUniq<ReadMLPMiddle>::__single_object std::make_unique<ReadMLPMiddle, std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&>(std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&) /workspace/build/REC/REC_HEAD/Calo/CaloTools/src/TMV_MLP_middle.C:192
#3 0x7f3122b25890 in GammaPi0SeparationTool::initialize() /workspace/build/REC/REC_HEAD/Calo/CaloTools/src/GammaPi0SeparationTool.cpp:61
#4 0x7f31ad0ef678 in operator() /workspace/build/GAUDI/GAUDI_HEAD/GaudiKernel/src/Lib/AlgTool.cpp:192