third_party: Fix labels so they can be used from within new_local_repository

Change-Id: Ic2969d328e211e3d977efeb2f778aceec1416a27
diff --git a/third_party/grpc/build_defs.bzl b/third_party/grpc/build_defs.bzl
index 4f88442..521ea43 100644
--- a/third_party/grpc/build_defs.bzl
+++ b/third_party/grpc/build_defs.bzl
@@ -52,7 +52,7 @@
             single_file = True,
         ),
         "_java_plugin": attr.label(
-            default = Label("//third_party/grpc:grpc-java-plugin"),
+            default = Label("@//third_party/grpc:grpc-java-plugin"),
             executable = True,
             cfg = "host",
         ),
@@ -96,9 +96,9 @@
       srcs = [gensource_name],
       visibility = visibility,
       deps = [
-          "//third_party:jsr305",
-          "//third_party/grpc:grpc-jar",
-          "//third_party:guava",
+          "@//third_party:jsr305",
+          "@//third_party/grpc:grpc-jar",
+          "@//third_party:guava",
           "@com_google_protobuf//:protobuf_java",
       ] + deps,
       **kwargs
diff --git a/third_party/protobuf/3.2.0/BUILD b/third_party/protobuf/3.2.0/BUILD
index 614c5cb..3621954 100644
--- a/third_party/protobuf/3.2.0/BUILD
+++ b/third_party/protobuf/3.2.0/BUILD
@@ -30,7 +30,7 @@
     jars = ["libprotobuf_java_util.jar"],
     visibility = ["//visibility:public"],
     exports = [
-        "//third_party:gson",
+        "@//third_party:gson",
     ],
 )