update omnibus-sw to pull in ruby CFLAG updates
support omnibus removal on all platforms

This mainly targets platforms where omnibus chef is installed with self-
extractable archives (makeself).
move linux build lab to a subfolder

This will allow the build lab to better support other non-linux
platforms.
ensure Berksfile exists in root of repository

The Berksfile is used by things other than Vagrant, like our CI scripts.
Document `CHEF_GIT_REV` usage for setting Chef version
update to Omnibus 1.0.3

This release contains FreeBSD and SmartOS support.
update to omnibus-software 239315117e

This release contains FreeBSD support.
Update to Omnibus cookbook 1.0.2

This release contains FreeBSD and SmartOS support.
[CHEF-4141] add FreeBSD build lab
Merge branch 'CHEF-4141'
update to omnibus-software 67307717f6

This release contains SmartOS support.
[CHEF-2576] adjust post inst/rm scripts for SmartOS

SmartOS writes data to `/opt/local` so we should link data to
`/opt/local/bin` instead of `/usr/bin`.
[CHEF-2576] add SmartOS build lab
Merge branch 'CHEF-2576'
pin windows gems to known good versions

This is a quick fix for an issue where unpinned versions of gems are
getting installed on windows. The test phase of the omnibus builds is
using bundler, so the tests use version constraints in the Gemfile,
while chef/knife in the actual package are not running with bundler and
so use the unconstained gem versions as installed by omnibus. A recent
release of the ffi gem had a bug in its error handling, which is causing
problems for chef users on windows. See: CHEF-4145
Merge branch 'pin-windows-gem-versions'
[CHEF-4163] update to omnibus-software d71bc0ace5

This version of omnibus-software contains a fix for nurses LDFLAGS:

Use `-R` instead of `-Wl,-rpath`. FreeBSD `ld` does not recognize the
`-Wl,-rpath` option.
Merge branch 'CHEF-4163'
update ob-software for libgcc dependency fix.

See:
https://github.com/opscode/omnibus-software/commit/9efe62f865260eb631ec30cd89eb3901140ff2f4
CHEF-4183 - Include 8.3 & 9.1 32/64 bit build baseboxes