Use a bool for ForceDefaults instead of an int

The actual function takes a bool.

While we are doing this, add a couple missing ForceDefaults.

Change-Id: I7fd41c048dae340ca4f339230ceb033349db0faf
diff --git a/frc971/zeroing/imu_zeroer_test.cc b/frc971/zeroing/imu_zeroer_test.cc
index 9ec52da..8eef149 100644
--- a/frc971/zeroing/imu_zeroer_test.cc
+++ b/frc971/zeroing/imu_zeroer_test.cc
@@ -7,7 +7,7 @@
 aos::FlatbufferDetachedBuffer<IMUValues> MakeMeasurement(
     const Eigen::Vector3d &gyro, const Eigen::Vector3d &accel) {
   flatbuffers::FlatBufferBuilder fbb;
-  fbb.ForceDefaults(1);
+  fbb.ForceDefaults(true);
   IMUValuesBuilder builder(fbb);
   builder.add_gyro_x(gyro.x());
   builder.add_gyro_y(gyro.y());