Change --yum-lock-timeout option action to store.

Yum was failing because the `--yum-lock-timeout` option's action was `"callback"`, and no callback function was provided, or needed. Manually verified on CentOS 6.4 that `sudo chef-apply -e "package 'httpd'"` successfully installs the httpd package.

I'm looking into the tests right now to see why they weren't failing.

\cc @opscode/client-eng