devel/py-asn1: Fix version numbers going backwards

Although this is a new port but there was an entry in the MOVED file
from 2015 when devel/py-asn1 was moved to devel/py-pyasn1 to match the
upstreaming rename. This entry from MOVED was not removed while adding
the new port.

Reported by: eugen
Approved by: portmgr (just-fix-it)