HEADS UP - last minute (non-bug-fix) HAMMER change to master/slave operation

[Matthew Dillon]

    I've decided to remove some confusion from the HAMMER utility, and also
    remove some of the master id code from the filesystem, which was
    designed for multi-master mode but really added confusion to the
    whole master-slave setup since we don't support multi-master mode
    in this release.

    PFS's will now only be master or slave, there will be no master id 
    (0-15) setting and there will not be a no-mirror mode.  A single
    whole-mount master id or no-mirror mode can be specified at mount
    time which is how I had it originally.  That way the master_id is
    out of sight and out of mind for the release.

    I am also removing the 'master' and 'slave' options to pfs-update,
    simplifying the PFS features.  Now you can create a master, create a 
    slave, upgrade a slave to a master, or downgrade a master to a slave.
    The confusing 'no-mirror', 'master=' and 'slave' options have been
    removed.

    I'll update the hammer.5 and hammer.8 docs appropriately, as well.

						-Matt