Increase the anti-jitter threshold for status bar flings.

You must move the panel at least 20dp overall, or at a speed
of 150dp/sec or more (actually quite easy; most normal
flings are 500dp/s or more) for it to be considered a fling.

Bug: 7179458
Change-Id: Ic1f4edc641cd2aa1cde89b2ee02eefdf5a0cc044