evas_cache_image: drop image after replacement

Summary:
When a newly created Image_Entry works for instead of an old one,
we need to drop it. And we did dorp it.

The line calling ref and drop was added by following commit.

   d550190 evas image cache - add lots more locking to try stamp out
           any thread bug

But it is missed by following commit.

   9f99ab1 evas cache: clear up caching locking and reference count.

Reviewers: Hermet, raster, jsuya, cedric

Reviewed By: cedric

Subscribers: cedric, #reviewers, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D10333

src/lib/evas/cache/evas_cache_image.c

@@ -1103,6 +1103,9 @@ evas_cache_image_size_set(Image_Entry *im, unsigned int w, unsigned int h)
    im2->references = 1;
    im2->flags.loaded = EINA_TRUE;
    if (cache->func.debug) cache->func.debug("size_set", im2);
+   /* this drop is for handling refereces in this function */
+   evas_cache_image_drop(im);
+   /* we don't need im at this point, drop it! */
    evas_cache_image_drop(im);
    return im2;
 
@@ -1110,6 +1113,9 @@ on_error:
    SLKL(engine_lock);
    if (im2) _evas_cache_image_entry_delete(cache, im2);
    SLKU(engine_lock);
+   /* this drop is for handling refereces in this function */
+   evas_cache_image_drop(im);
+   /* we don't need im at this point, drop it! */
    evas_cache_image_drop(im);
    return NULL;
 }