Set gazelle:prefix on staging/src and remove sed hack

hack/update-bazel.sh

@@ -41,11 +41,5 @@ gazelle fix \
     -build_file_name=BUILD,BUILD.bazel \
     -external=vendored \
     -mode=fix
-# gazelle gets confused by our staging/ directory, prepending an extra
-# "k8s.io/kubernetes/staging/src" to the import path.
-# gazelle won't follow the symlinks in vendor/, so we can't just exclude
-# staging/. Instead we just fix the bad paths with sed.
-find staging -name BUILD -o -name BUILD.bazel | \
-  xargs ${SED} -i 's|\(importpath = "\)k8s.io/kubernetes/staging/src/\(.*\)|\1\2|'
 
 kazel

staging/src/BUILD

@@ -0,0 +1,4 @@
+# gazelle gets confused by our staging/ directory, prepending an extra
+# "k8s.io/kubernetes/staging/src" to the importpath.
+# Using this directive ensures that it sets the correct importpath.
+# gazelle:prefix