elementary: remove unnecessessary disabled setter

elementary: remove unnecessessary disabled setter

summary_:
those objects are disabled anyways, because disabled is applied to the
objects in a tree. Which means, subobjects of a widget are disabled
whenever the widget is disabled anyways.

Depends on D8015

Reviewers: cedric, zmike, segfaultxavi, stefan_schmidt

Reviewed By: segfaultxavi

Subscribers: cedric, #reviewers, #committers

Tags: #efl

Reviewed-by: Xavi Artigas <xavierartigas@yahoo.es>
Differential Revision: https://phab.enlightenment.org/D8016