scroller : Call mirrored_set function after edje_obj is initialized

scroller : Call mirrored_set function after edje_obj is initialized

Summary:
Problem that scroller is not mirrored in RTL mode has been fixed in D4908.
However, I found a problem in init process.
I will revert D4908 commit(https://phab.enlightenment.org/D4908).

After edje_obj is initialized, mirrored_set is called.
When wanted_region_set is called, x-coordinate flip normally and acts as RTL.

Test Plan: scroller test on elementary_test.

Reviewers: raster, woohyun, SanghyeonLee, akanad, eagleeye, cedric, singh.amitesh, eunue

Subscribers: jpeg, cedric

Differential Revision: https://phab.enlightenment.org/D4944