Fix year "1017" to be "2017" in a few places
Fix year "1017" to be "2017" in a few places

Metamath was not around before the Norman Conquest.  This fixes
the dates so the years coincide with a different Norman.

Signed-off-by: David A. Wheeler <9ae72d22d8b894b865a7a496af4fab6320e6abb2@dwheeler.com>

metamath/set.mm,metamath/set.mm,metamath/set.mm