- add an aliases attribute as a lookup of aliasname to canonical name
  of parameters
- add support for no_log attribute per-parameter which will not log
  that information to syslog
make sure ec2_secret_key is set to no_log=True
command: make sure that all _handle_aliases() calls returns {}
module_common: also work if there are no aliases (shell, command, etc) modules
Merge pull request #2198 from skvidal/nolog-params

No_log params