Revert "AP_NavEKF : Reduce ripple in estimates that can cause copter motor 'pulsing'"

This reverts commit 13df6fb1c9f1c42ddda3250fec3486212213463c.

This patch was a result of an incorrect merge of the optflow branch
into master. It reintroduced the bug fixed by this commit:

  AP_NavEKF : Fix bug in reset of GPS glitch offset
  8aa267f75fb1e7161505974b4ac2f7eef95a6cd1