Fixed a problem in the motd::knife-status recipe

When it gets the "interval" value from node['chef_client']['interval'],
it was failing to convert the seconds to minutes since the value
returned was actually a string. This fix just ensures that the
value in "interval" is actually an integer, so that we can do
math operations on it.

See: https://github.com/opscode-cookbooks/chef-client/blob/master/attributes/default.rb#L36
Fixed interval bug
Changed to using to_i method
Reverting change and actually fixing the damn thing
using Chef::Config cache_path instead of hardcoded path
Added custom matchers for ChefSpec
Reverted interval change
Merge pull request #3 from greglu/knife-status-recipe-fix

Fixed a problem in the motd::knife-status recipe
Merge pull request #6 from rafaelmagu/add_rspec_matchers

Add ChefSpec matchers and fixed interval bug
Merge pull request #5 from BarthV/cache_path

using Chef::Config cache_path instead of hardcoded path
Rename knife-status recipe to knife_status
Add travis linting tests (rubocop/foodcritic)
Bump version to 0.5.0, update CHANGELOG