VMM: Unified parameter names and option names.
handler: Handler.user_delete() renamed parameter:
delete_home -> del_dir
The same as in Handler.domain_delete().
cli/subcommands: renamed userdelete's option
--delete-home -> --delete-directory
So people have to memorize only one option name. It also matches the
setting names of vmm.cfg.
.. |curr_vers_rel_date| replace:: The most current version of vmm is 0.6.2,
released on 01 February 2014.
.. |rel_hist| replace:: Older releases are listed in the :doc:`release_history`.