Genlist: Focus does not move, if it is set on item content objects.

Genlist: Focus does not move, if it is set on item content objects.

Summary:
If focus is set on item content object, it's treated as a
         different object which results the focus deadlock. So, every
         time whenever focus sets on item content object, we need to
         unset and set the focus on genlist object. Thanks to Seoz for
         the idea.

Test Plan: elementary_test -to "genlist focus"

Reviewers: seoz, SanghyeonLee, eagleeye

CC: seoz
Differential Revision: https://phab.enlightenment.org/D891