ENYO-409: Handle case where date picker has not had a value set yet.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>
Merge pull request #1738 from enyojs/ENYO-409-aarontam

ENYO-409: Handle case where date picker has not had a value set yet.

Reviewed-By: Krishna Rangarajan (krishna.rangarajan@lge.com)
Integrated-By: Ryan Duffy (ryan.duffy@lge.com)