selectively move to client-go packages

pkg/auth/authorizer/union/BUILD

@@ -8,16 +8,6 @@ load(
     "go_test",
 )
 
-go_library(
-    name = "go_default_library",
-    srcs = ["union.go"],
-    tags = ["automanaged"],
-    deps = [
-        "//pkg/auth/authorizer:go_default_library",
-        "//pkg/util/errors:go_default_library",
-    ],
-)
-
 go_test(
     name = "go_default_test",
     srcs = ["union_test.go"],
@@ -25,3 +15,13 @@ go_test(
     tags = ["automanaged"],
     deps = ["//pkg/auth/authorizer:go_default_library"],
 )
+
+go_library(
+    name = "go_default_library",
+    srcs = ["union.go"],
+    tags = ["automanaged"],
+    deps = [
+        "//pkg/auth/authorizer:go_default_library",
+        "//vendor:k8s.io/client-go/pkg/util/errors",
+    ],
+)

pkg/auth/authorizer/union/union.go

@@ -19,8 +19,8 @@ package union
 import (
 	"strings"
 
+	utilerrors "k8s.io/client-go/pkg/util/errors"
 	"k8s.io/kubernetes/pkg/auth/authorizer"
-	utilerrors "k8s.io/kubernetes/pkg/util/errors"
 )
 
 // unionAuthzHandler authorizer against a chain of authorizer.Authorizer