paths.KDESTROY instead of "kdestroy" and paths.GETENT instead of "getent"

Affected modules:
  roles/ipaclient/library/ipahost.py
  roles/ipaclient/library/ipajoin.py
  roles/ipaclient/library/ipanss.py

The directories library and action_plugins do only contain ipaclient specific
modules and plugins. Therefore these directories should be located in the
ipaclient role directory.