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.