update BUILD files

vendor/github.com/coreos/etcd/wal/BUILD

@@ -18,6 +18,7 @@ go_library(
         ],
         "//conditions:default": [],
     }),
+    importpath = "github.com/coreos/etcd/wal",
     visibility = ["//visibility:public"],
     deps = [
         "//vendor/github.com/coreos/etcd/pkg/crc:go_default_library",

vendor/github.com/coreos/etcd/wal/walpb/BUILD

@@ -6,6 +6,7 @@ go_library(
         "record.go",
         "record.pb.go",
     ],
+    importpath = "github.com/coreos/etcd/wal/walpb",
     visibility = ["//visibility:public"],
     deps = ["//vendor/github.com/golang/protobuf/proto:go_default_library"],
 )