Merge pull request #1871 from opscode/lcg/supermarket-urls

Lcg/supermarket urls
Conflicts:
	CHANGELOG.md
	spec/unit/knife/cookbook_site_download_spec.rb
	spec/unit/knife/cookbook_site_share_spec.rb
Merge pull request #2240 from opscode/sersut/backport-supermarket-switch

Backport cookbooks.opscode.com -> supermarket change to 11-stable.