Pull state out of the zeroing estimators more nicely

I'm eventually going to remove the position() member, but for now Austin
wants this too.

Change-Id: I12b0c01eb5174751bd04fee8fdb770378a87f541
diff --git a/y2015/control_loops/claw/claw.cc b/y2015/control_loops/claw/claw.cc
index 987bb5e..25b5b9d 100644
--- a/y2015/control_loops/claw/claw.cc
+++ b/y2015/control_loops/claw/claw.cc
@@ -281,8 +281,7 @@
   status->zeroed = state_ == RUNNING;
   status->estopped = state_ == ESTOP;
   status->state = state_;
-  ::frc971::zeroing::PopulateEstimatorState(claw_estimator_,
-                                            &status->zeroing_state);
+  status->zeroing_state = claw_estimator_.GetEstimatorState();
 
   status->angle = claw_loop_->X_hat(0, 0);
   status->angular_velocity = claw_loop_->X_hat(1, 0);