Precisely specifying the Salt version
Precisely specifying the Salt version

Newly created minions are at 2016.3.4, while older machines are at 2016.3.1 which has a bug that doesn't show `Total run time: ... s` when running highstate.

Since the grep in `scripts/bootstrap.sh` is on this value, the version did not get upgraded. With this change, everyone will get `2016.3.4`.

elifesciences/builder,elifesciences/builder