Summary:
genlist content_get sometimes work weird after reusable_content_get pushed.
cached content is shown even content_get function is not exist or
return NULL.
now cache check item_class instead of item style string.
Test Plan: check genlist cache in elementary_test
Reviewers: Hermet, cedric, raster
Subscribers: Jaehyun_Cho, jpeg
Differential Revision: https://phab.enlightenment.org/D3921
Conflicts:
src/lib/elementary/elm_genlist.c
SangHyeon Lee
Cedric BAIL