Save on solid-form-image should not empty the field

Core 0.17.

With a solid-form, using a solid-form-image*, having a value - or a value coming from the data-src - should not be rewritten as blank when saving.

https://jsbin.com/yaloyisato/edit?html,output

Follow #802 (closed)
Same issue, but when the field is not empty, it should not be emptied.


On page load image
After saving 1-time - notice that the resource is unchanged, it still have the proper value image

If the visitor do another save, the resource is emptied, as expected but unwanted.


@balessan @manonbou