OS-2253 when rebooting many zones, mdata:fetch should not go into maintenance
OS-2289 make metadata agent files jsl and jsstyle clean
OS-2290 switch metadata agent to bunyan logging
OS-2291 cleanup objects for zone when zone deleted
OS-2292 fix KEYS command to merge internal_metadata creds w/ customer_metadata keys
OS-2293 upgrade node-zsock to latest upstream