Fixes for building with old cmake
I needed few minor fixes to be able to build LHCb/master with old cmake. That includes:
- Python 2to3 migration issue (see !44 (closed))
- removed
CMAKEFLAGSsince it was causingconfigureto fail, and-C...cache_preload.cmakeis passed anyway (it's being passed twice in the old system, see https://lhcb-nightlies.web.cern.ch/nightly/lhcb-master/1382/LHCb/x86_64-centos7-gcc9-opt/build#configure_2) - passing
CMAKE_USE_CCACHEfrom slot configuration to the build functions - fix patching the log filename (to account for the fact that
makecommands are run from e.g./workspace/LHCb/directory not/workspace/as in the new cmake)