Follow up to r290259 dealing with makefs(8)

• Don't use contractions (don't -> do not)
• Change "throw away" to "discard" when describing the -o keep-bad-images option
• Revert author e-mail split I brought over from NetBSD, effectively reverting the change bapt made in r267668

MFC after: 3 days
Submitted by: bjk
Sponsored by: EMC / Isilon Storage Division