Parsing ignores currency provided by with_currency block

[elfassy]

[1] pry(main)> Money.with_currency('KWD') { Money.parse("100.000") }
=> #<Money value:100000.000 currency:KWD>
[2] pry(main)> Money.parse("100.000")
=> #<Money value:100000.00 currency:>
[3] pry(main)> Money.parse("100.000", 'KWD')
=> #<Money value:100.000 currency:KWD>

cc @bdewater