Verify that `node_path` is a String
Verify that `node_path` is a String

`node_path` made it back to Chef's default configuration in 11.8.0. And
as pre 0.3.0 setups won't normally have it explicitly configured, it
defaults to being an Array.

Also a user might set it to be an Array, which leads knife-solo crashing
with the infamous `ERROR: TypeError: no implicit conversion of Array
into String`. This escaped from us in GH-300.

coletivoEITA/knife-solo,analog-analytics/knife-solo,a2ikm/knife-solo,coletivoEITA/knife-solo,a2ikm/knife-solo,chadzilla2080/knife-solo,a2ikm/knife-solo,leonid-shevtsov/knife-solo,leonid-shevtsov/knife-solo,coletivoEITA/knife-solo,analog-analytics/knife-solo,chadzilla2080/knife-solo,chadzilla2080/knife-solo,analog-analytics/knife-solo,leonid-shevtsov/knife-solo,matschaffer/knife-solo,matschaffer/knife-solo,matschaffer/knife-solo