Changing 2017 constants from aos::Once to absl::call_once()

Change-Id: I0f0ef84c77e5e71171836a478c761398c342f017
diff --git a/y2017/BUILD b/y2017/BUILD
index 30da3b9..404683b 100644
--- a/y2017/BUILD
+++ b/y2017/BUILD
@@ -13,6 +13,7 @@
         "//aos:once",
         "//aos/logging",
         "//aos/mutex",
+        "@com_google_absl//absl/base",
         "//aos/network:team_number",
         "//frc971:constants",
         "//frc971/shooter_interpolation:interpolation",