Reattach header view after DPAD scroll.

A header view that was scrolled off screen using the DPAD would not be
reattached properly when scrolled back into view, due to the flag
recycledHeaderFooter. Solved this by using detachViewFromParent()
instead of removeViewInLayout(). Compare to
AbsListView.trackMotionScroll().

Change-Id: I0ac0ec0f9bf23bc62430c1f62ae7d1a8570b0a24