Allow enyo.Image to be "unset" even when using a sizing property.

Enyo-DCO-1.1-Signed-off-by: Blake Stephens <blake.stephens@lge.com>
Fixing spacing to match standard.

Enyo-DCO-1.1-Signed-off-by: Blake Stephens <blake.stephens@lge.com>
Merge pull request #841 from enyojs/BHV-13445-blakestephens

BHV-13445: Allow enyo.Image to be "unset" even when using a sizing property.

Reviewed-By: Cole Davis (cole.davis@lge.com)