interface_scrollable: delete unnecessary smart callback call.

interface_scrollable: delete unnecessary smart callback call.

Summary:
When _elm_interface_scrollable_page_bring_in is called, page is not changed yet.
So "page,changed" smart callback is unnecessary.

Sometimes "page,changed" smart callback is called twice.
Because "drag,stop" and "anim,stop"is called it.
So I add updating current page code.

Test Plan:
elementary_test -> scroller

1. using wheel.
2. using "prev page" and "next page".
3. draging sceen

Reviewers: Hermet, singh.amitesh, cedric, raster, jaehwan, seoz

Differential Revision: https://phab.enlightenment.org/D3260

Signed-off-by: Cedric BAIL <cedric@osg.samsung.com>