fix specs broken due to JSON monkeypatching issues

yajl/ffi-yajl vs JSON whitespace issues
Merge pull request #1802 from opscode/lcg/fix-travis

fix specs broken due to JSON monkeypatching issues
Issue 1754: Chef::Exceptions::Env exception when modifying env resource using key_name attribute that differs in case from the environment variable name
Change encoding to Unix, remove inaccuracy in example description
Merge pull request #1774 from opscode/adamedx/issue-1754-windows-env

Issue 1754: Chef::Exceptions::Env exception when modifying env resource ...
remove JSON gem usage

should fully convert to using ffi-yajl

there are still issues with JSON gem monkeypatching interacting with
chef-zero and the spec tests so we keep the requires here for the
json gem and the ffi_yajl/json_gem here.  when ohai and chef-zero are
fixed, we an just require ffi_yajl.