Fix cookbook stripping for Berkshelf v3
Fix cookbook stripping for Berkshelf v3

Berkshelf v3 installs Berksfile.lock to the cookbooks folder. Ignore it.

mlafeldt/chef-runner,mlafeldt/chef-runner,rajthilakmca/chef-runner,rajthilakmca/chef-runner,rajthilakmca/chef-runner,mlafeldt/chef-runner