Allow pool names that look like Solaris disk names
Nothing bad happens if a prefix of your pool name matches a disk name.
This is a bit of a silly restriction at this point.
Reviewed-by: Richard Laager <firstname.lastname@example.org>
Reviewed-by: Brian Behlendorf <email@example.com>
Reviewed-by: George Melikov <firstname.lastname@example.org>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>