Update Vagrant stack (and fix broken Gem dependencies)

[gildegoma]

Notes:

• I first started to create very conservative Gem dependency settings (e.g. Vagrant ~1.1, Berkshelf ~1.4, vagrant-berkshelf ~1.1), to fix travis broken build. On my way, I finally found better to go forward and make the Vagrant dependency more up to date. Hope you like it...
• I have no experience in rubygems publication and thus I preferred not to bump gem.version. But since [https://rubygems.org/gems/minitest-chef-handler](version 1.0.1) is already published, I guess that if this PR is accepted, this value should be changed... (to 1.0.2 or 1.1.0?)

Changes:

• Gemfile and minitest-chef-handler.gemspec are now more restrictive about dependency versions
• Use latest Vagrant version (1.3.3)
• Vagrantfile is now in configuration format "2" (only compatible with Vagrant 1.1+)
• Vagrantfile refers to an explicit basebox (so that tests behave the same for all contributors)
• Two tests were adapted to pass with new basebox
• Skip two failing tests (it looks like these problems should be fixed in sublayers, like Chef resources API or minitest. to be investigated).

Not done yet (no tested yet, and to be discussed):

• Like specs, should we run the Vagrant tests twice (also against Chef 10?)
• Is an update to minitext 5.0.x straightforward (and recommended)?

[calavera]

Is an update to minitext 5.0.x straightforward (and recommended)?

No it's not straightforward, nor recommended. The minitest internals have changed a lot, requiring more monkey patching to make this work. I think those problems could be addressed with https://github.com/seattlerb/minitest/pull/295, but as you can see it never got merged.

[gildegoma]

Thanks @calavera for the precisions. On my side, I don't need anything else for this PR.

Still open:

• Do you accept to break backward compatibility with Vagrant 1.0.x (and even force usage of 1.3+)
• disabled tests ("Upstart"-service not seen as enabled, "Nil owner" on a directory)
• Vagrant tests only run against Chef 11.6.0

What do you think?