Salt node config was ignoring the npm dependency

According to the Salt documentation
http://docs.saltstack.com/en/latest/ref/states/all/salt.states.npm.html

npm must be installed in order to use the npm.installed state manager.
node/init.sls was not setting npm to be installed.
Merge pull request #1 from lytics/lio1626_fix

Salt node config was ignoring the npm dependency