Side-project feature request for 'hammer mirror-*' functions

[Matthew Dillon]

    If someone has the time, this is a really simple feature request.
    Ok, yah, I could do it myself, but I'm going to offer it to others
    first and that might save me a little time :-)

    It's simple.  If you do a hammer mirror-copy or hammer mirror-stream
    to a target HAMMER filesystem the code checks that the target is a PFS
    slave with the same shared UUID as the master's UUID.

    I want a feature that asks the user whether he wants to create a
    conforming PFS on the target at that point, if the target directory
    does not exist, instead of exiting with an error.

    i.e. this would take away all the effort of having to create a pfs-slave
    and assign the correct UUID to it.  It takes about 60 seconds and some
    cutting and pasting to do that manually now... not long, but we can
    make it ultra convenient.

    You would simply run the command and it would ask if you wanted to create
    a new PFS on the target instead of exiting.  You would say 'yes', and
    poof, new mirror slave target :-).

					-Matt