[GNC] Entering a 2-digit year generates the wrong date

[Chris Velevitch]

 When I enter a new transaction with a 2-digit year, the resultant date
becames1899. For example, I enter 10 for the year and I get 1899 when I
expect to get 2010. This worked in 2.x.



Mac OSX: 10.11.6, GnuCash 3.2+ (2018-06-24)