naviframe: Fix smart_show function to show only top item view
naviframe: Fix smart_show function to show only top item view

Summary:
Now if evas_object_show is called for naviframe, all item views are shown.
This may cause the previous item view is overlapped to the top item view.
To resolve this problem, fix smart_show of naviframe to show only top item view.
@fix

Reviewers: Hermet

CC: seoz

Differential Revision: https://phab.enlightenment.org/D594

FlorentRevest/Elementary,tasn/elementary,tasn/elementary,FlorentRevest/Elementary,FlorentRevest/Elementary,FlorentRevest/Elementary,rvandegrift/elementary,tasn/elementary,rvandegrift/elementary,rvandegrift/elementary,tasn/elementary,rvandegrift/elementary,tasn/elementary