Spree::Price parsing was returning 0.0 when given a an empty string as
price, resulting in a variant being valid even if no price was given. It
only happened if `Spree::LocalizedNumber` wasn't used.
Spree::LocalizedNumber` return nil if given a blank number.
An error was apparent in specs when trying to assign a string as the price. It's not a problem when submitting the form in the browser, I don't know why.
But in any case, it shouldn't be trying to modify a variable passed as a parameter.
Increases the maximum number of digits (on the left side of the decimal place) that the column can hold, to allow larger values. This change is made in Spree 2.2 and is relevant in cases with either large order values, or certain currencies that have large values as standard. For example, 100 UK Pounds is roughly 4000 Thai Baht. 1 million pounds is unlikely to ever be needed as a value, but 1 million Baht is not so unlikely...
