CHEF-4962, knife ssh will use a cloud atttribute for port if available.

The Azure cloud can have multiple nodes behind a single ip/fqdn
with different ssh ports for each. knife ssh should be able to
run on a search of nodes and use the correct ssh port for each.
Change ssh port attribute to use cloud, reorder priority.
Refactor node search for knife ssh.
Merge pull request #1213 from MSOpenTech/CHEF-4962

CHEF-4962, knife ssh will use a cloud attribute for port if available.