Remove ewk_view_use_smart_selection_set() API because it is not used anymore.

Remove ewk_view_use_smart_selection_set() API because it is not used anymore.

[Title] Remove ewk_view_use_smart_selection_set() API because it is not used anymore.
[Issue#] N/A
[Problem] ewk_view_use_smart_selection_set() is not used anymore.
[Cause] The ewk_view_use_smart_selection_set() was added for testing desktop web applications,
        but it is not used anymore and smart_selection is default behavior of ewk_view.
        If user want to disable zoom, he/she can set scalable variable to false in the viewport tag of web pages.
[Solution] Remove ewk_view_use_smart_selection_set().

Change-Id: I16dc69f9da1a5a2591428517af99671854c99715