evas_object_image: render_post returns if preloading.
The render_post calls evas_object_change if o->changed is true which is added
by commit "36fc2e6 evas image: fix non-rendered preload image.".
But an image could lose chance to render. Please refer to the following.
(1) 1st render_updates_internal
render_post - evas_object_change for image and its parents evas_object_reset - for its parent
(2) _evas_image_load_post_update - o->preload is changed to true here
(3) 2nd render_updates_internal
evas_render_mapped cannot call render
The reason of (3) would be unchanged parents.
If render_post returns if an image is preloading, then evas_object_change works
for the image and its parents at (2). And finally (3) will call render.
It would be reasonable because render_pre, and render returns as well.
Reviewed-by: Cedric BAIL <email@example.com>
Differential Revision: https://phab.enlightenment.org/D7973