Datepicker: Correct the Finnish date format

The correct Finnish date format is `d.m.yy`, not `dd.mm.yy`.

Sources:
[Kotimaisten kielten keskus (in Finnish)](http://www.kotus.fi/index.phtml?i=519&s=2614#faq_519)
[Nykyajan kielenopas (in Finnish)](http://www.cs.tut.fi/~jkorpela/kielenopas/5.2.html#paivays)
[Finnish Style Guide (in English)](http://download.microsoft.com/download/7/e/8/7e814349-60ae-4208-b4f8-b454d201dcbb/fin-fin-StyleGuide.pdf)
[IBM: Finnish locale (in English)](http://pic.dhe.ibm.com/infocenter/forms/v3r5m1/index.jsp?topic=%2Fcom.ibm.form.designer.locales.doc%2Fi_xfdl_r_formats_fi_FI.html)