Fix lvcreate corelog validation.

  Fix lvcreate corelog validation.
  Add --config for overriding most config file settings from cmdline.
  Quote arguments when printing command line.
  Remove linefeed from 'initialising logging' message.
  Add 'Completed' debug message.
  Don't attempt library exit after reloading config files.
  Always compile with libdevmapper, even if device-mapper is disabled.