[Midnightbsd-cvs] src: disks.c: add some helpful error messages.

[laffer1 at midnightbsd.org]

Log Message:
-----------
add some helpful error messages.

Modified Files:
--------------
    src/usr.sbin/sysinstall:
        disks.c (r1.5 -> r1.6)
        (http://cvsweb.midnightbsd.org/src/usr.sbin/sysinstall/disks.c?r1=1.5&r2=1.6)