fix NAS-Port-Id sql error

queries.conf :
NAS-Port-Id not updated correctly in mysql because the value inserted
was %{NAS-Port} instead of %{NAS-Port-Id} (if sent by NAS) or
%{NAS-Port} (if NAS-Port-Id not sent by NAS)

schema.sql :
altered column nasportid from varchar(15) to varchar(50) to allow bigger
NAS-Port-ID information (maximum from RFC 2869 is 253 octets, but 50
should be enough)

(initial pull request # 468 was modified as discussed)