index_example_01.c: fixed wrong example code. elm_index_level_go() should be called after every index item changes.
index_example_01.c: fixed wrong example code. elm_index_level_go() should be called after every index item changes.

This fixes T510.

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