Check whether Salt bootstrap script exists before attempting to delete it. GH-4614
Force compatible Bundler version in Travis
Merge pull request #4625 from tmatilai/travis_bundler

Force compatible Bundler version in Travis
docs - http sharing: fix typo
Merge pull request #4632 from janek-warchol/patch-1

docs - http sharing: fix typo
Allow SSH LogLevel to be overridden
Merge pull request #4638 from julienvey/ssh_log_level

Allow SSH LogLevel to be overridden in Vagrant.Util.SSH.exec
whitespace
Merge pull request #4615 from styro/fix/master/issue-4614

provisoiners/salt: Check whether Salt bootstrap script exists before deleting it. GH-4614
Update CHANGELOG
Update wording for unreleased boxes