Make zk_init resource attribute-driven in server recipe.
Merge pull request #4 from hw-cookbooks/server-refactors

Server refactorings
Add support for unit testing.
Add spec coverage for recipe[zookeeperd::client].
Add optional runit support for process supervision.
Add TravisCI testing <3 <3 <3
Update server recipe specs.
Make zk_init resource attribute-driven in server recipe.
Remove unused node attributes for runit.
Rename attr to zookeeperd/init for runit support.
Use different actions on service depending on init type.
Fix unit tests due to server -> init attr update.