invalid boolean check for limit/offset clause in firebird

[Mike Bayer]

from sqlalchemy import table, column, select
from sqlalchemy.dialects import firebird


t = table('test', column('id'))
stmt = select([t]).limit(5)


print(stmt.compile(dialect=firebird.dialect()))

regression in 1.0 due to #3034

[Mike Bayer]

pr at https://github.com/zzzeek/sqlalchemy/pull/168

[Mike Bayer]

changelog for #3380, fixes #3380

→ <<cset 167a45a442a2>>