choose the 'legacy' VelocityTracker strategy

the msm touchscreen gives fairly noisy positions as fingers are lifted and this
is a known problem for the default android 4 'lsq2' VelocityTracker Estimator
strategy. instead use the 'legacy' strategy as it deals with noise better.
experiments show that the 'int1' strategy also isn't too bad.
Revert "use smartassV2 governor by default"

This reverts commit 83ee7a3ecd781d56c82cb2dcc1d53c852790606b.