Fixed node_name to be server.host

I know it calls it above, but it seems that it hasn't worked for a while
This does work, and allows us to see machines knife ssh fails to connect
to.
[CHEF-3812] Support a --before option in "knife node run_list add"
[CHEF-3812] Update test to check for ui.fatal
[CHEF-3812] Split up methods into _before and _after for clarity.
Add release notes for a contributions merge

* CHEF-4918 - Override attributes saved as normal attributes after 2 runs.
* CHEF-5029 - Warnings et al telling what machines running knife ssh connecting to arent displayed
* CHEF-3812 - knife node run_list add needs a 'before' option
[CHEF-4918] Don't destructively merge subhashes in hash_only_merge!

hash_only_merge dups its inputs and then passes it to
hash_only_merge!.  Unfortunately, dup does not make a deep copy,
leading hash_only_merge to mutate deeply nested structures.