Tweak for new Bazel which doesn't conflate repositories

Change-Id: I302c7edb067a6854e04a4b6157622b7e9846eec7
diff --git a/debian/usr.BUILD b/debian/usr.BUILD
index c66b30d..7ee1bf3 100644
--- a/debian/usr.BUILD
+++ b/debian/usr.BUILD
@@ -1,4 +1,4 @@
-package(default_visibility = ['//debian:__pkg__'])
+package(default_visibility = ['@//debian:__pkg__'])
 
 cc_library(
   name = 'librt',