Set default roboRIO to something legal.

Change-Id: I525efce39237c2dfd1ca6c4e4c50bc14913fa6e2
diff --git a/aos/downloader/downloader.bzl b/aos/downloader/downloader.bzl
index 51d6916..a98571a 100644
--- a/aos/downloader/downloader.bzl
+++ b/aos/downloader/downloader.bzl
@@ -55,7 +55,7 @@
       allow_files = True,
     ),
     'default_target': attr.string(
-      default = 'roboRIO-971.local',
+      default = 'roboRIO-971-frc.local',
     ),
   },
   executable = True,