(maint) Allow beaker version to be overridden
(maint) Allow beaker version to be overridden

Allow beaker gem version to be overridden as an environment variable,
e.g. export BEAKER_VERSION=git://github.com/puppetlabs/beaker#<sha>

This also changes the default beaker version from ~> 2.2.0 to the master
branch for now.

ferventcoder/hiera,ferventcoder/hiera,Iristyle/hiera,johnduarte/hiera,ferventcoder/hiera,Iristyle/hiera,MikaelSmith/hiera,johnduarte/hiera,johnduarte/hiera,Iristyle/hiera,MikaelSmith/hiera,MikaelSmith/hiera