NumberPicker: Set formatter local value to US.

As the Arabic language formatter would make number "1,2,3" to Arabic
language word means one,two,three, NumberPicker won't like to show
any thing other than numbers, add local settings to US, make the
number 1,2,3

Change-Id: If2d161ac4133f6c9c6e1ec284d6d2fbf01855fa0