edje: fix memory leak detected by prevent static analyser.

Summary:
Modified codes according to prevent result
The im will be freed by data_image_preload_done api.
But if image load error happen, never call that api

@fix

Test Plan: prevent tool

Reviewers: Jaehyun, Hermet, cedric

Reviewed By: cedric

Subscribers: cedric

Differential Revision: https://phab.enlightenment.org/D2565

Signed-off-by: Cedric BAIL <cedric@osg.samsung.com>

src/bin/edje/edje_cc_out.c

@@ -1048,6 +1048,7 @@ data_write_images(Eet_File *ef, int *image_num)
                     }
                   else
                     {
+                       if (iw) free(iw);
                        error_and_abort_image_load_error
                          (ef, img->entry, load_err);
                        exit(1); // ensure static analysis tools know we exit