List: Focus does not move if it's set on item content object.

List: Focus does not move if it's set on item content object.

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 "list focus"

Reviewers: seoz, SanghyeonLee, eagleeye

CC: seoz
Differential Revision: https://phab.enlightenment.org/D973