Decrease sensitivity of orientation changes a bit.

I've noticed over the past couple weeks that my phone was flipping to
landscape when I placed it down too often, more like it did in Eclair.
I think my previous changes to make orientation changes quicker were a
bit too aggressive, so I'm backing off a couple of the time constants.

Change-Id: Ifffd45ac934984cc9091da56958bc2b6bcaa280a