notify observers of currentValueText when locale changes
notify observers of currentValueText when locale changes

For subkinds of DateTimePickerBase, the value of currentValueText is
formatted for the locale. The local locale member is deprecated by
ENYO-1859 so we must manually notify observers of currentValueText to
refetch its value when the locale changes.

Issue: ENYO-2516
Enyo-DCO-1.1-Signed-off-by: Ryan Duffy (ryan.duffy@lge.com)

enyojs/moonstone