Additions to 'hammer pfs-*':

Additions to 'hammer pfs-*':

    * Add 'snapshots=dir' and 'snapshots-clear' options

      This allows you to specify the snapshots directory for any PFS, master
      or slave.  The option will override the default "snapshots"
      sub-directory used by the 'hammer cleanup' directive for PFS masters.

      This option is required for PFS slaves since the hammer cleanup
      directive cannot use a directory in the slave PFS as a working
      directory (because its a slave).

Additions to 'hammer cleanup':

    * Implement the snapshot limit found the config file.  e.g. if the
      <fs>/snapshots/config file contains: 'snapshots 1d 60d' then
      the filesystem is snapshotted once a day and snapshot softlinks over
      60 days old will be deleted.

    * This directive now checks the snapshots path configured in the PFS
      and uses it if it is not empty.  The snapshots path must be configured
      for slaves.