evas: opaque value does not change even if image data be changed
Summary:
opaque value keeps previous image's value
when image data be changed by file_set/mmap_set api
@fix
Test Plan:
1) Make a evas rectangle object has color
2) Make a evas image object with jpg file.
3) Replace image data with png file by evas_object_image_file_set.
Reviewers: Hermet, cedric, jypark
Subscribers: cedric
Differential Revision: https://phab.enlightenment.org/D2774
Signed-off-by: Cedric BAIL <cedric@osg.samsung.com>