Chop out the MotorDanger junk

It had race conditions, and the inheritance hierarchy is a mess.

Change-Id: I4566ee5d7a53ec162c885a70bef3e2774555eef7
diff --git a/third_party/allwpilib_2017/BUILD b/third_party/allwpilib_2017/BUILD
index 054ef08..1903912 100644
--- a/third_party/allwpilib_2017/BUILD
+++ b/third_party/allwpilib_2017/BUILD
@@ -46,6 +46,11 @@
   'ADXRS450_Gyro',
   'GyroBase',
   'IterativeRobot',
+  'MotorSafety',
+  'MotorSafetyHelper',
+  'SafePWM',
+  'SpeedController',
+  'PWMSpeedController',
 ]
 
 # Whole subdirectories of WPILib we don't want around.