Set priority of spline worker thread.

Change-Id: I1795be4dd16aac048effdcc54768b73d62db7dfb
diff --git a/frc971/control_loops/drivetrain/BUILD b/frc971/control_loops/drivetrain/BUILD
index 9b0400e..e332cfe 100644
--- a/frc971/control_loops/drivetrain/BUILD
+++ b/frc971/control_loops/drivetrain/BUILD
@@ -96,6 +96,7 @@
         ":drivetrain_queue",
         ":spline",
         ":trajectory",
+        "//aos:init",
     ],
 )