prevent popups hiding when enter pressed

Issue: ENYO-555
Enyo-DCO-1.1-Signed-off-by: Ryan Duffy (ryan.duffy@lge.com)
reset preventHide flag when popup showing changes

Issue: ENYO-555
Enyo-DCO-1.1-Signed-off-by: Ryan Duffy (ryan.duffy@lge.com)
Merge pull request #1824 from enyojs/ENYO-555-ryanjduffy-2.5

ENYO-555: moon.Popup doesn't capture Spotlight select

Integrated-By: Gray Norton (gray.norton@lge.com)