Fixing Travis: updated root binary to support Minuit

The root binary ([root_v5.34.14_Python_2.7.tar.gz](https://senkin.web.cern.ch/senkin/root_builds/root_v5.34.14_Python_2.7.tar.gz)) is now custom-built using 64-bit Ubuntu VM, and is now stored in my private lxplus area until @kreczko revives vivaldi.