build file updates to support bazel 0.21

Change-Id: I79d3900fc8c14dbecff249cec139754115186352
diff --git a/tools/build/bazel/generate_test_rules.bzl b/tools/build/bazel/generate_test_rules.bzl
index 03f5073..17f811e 100644
--- a/tools/build/bazel/generate_test_rules.bzl
+++ b/tools/build/bazel/generate_test_rules.bzl
@@ -61,7 +61,7 @@
         if (test in flaky_tests) or ("flaky" in tags):
             flaky = 1
         java_class = _package_from_path(
-            PACKAGE_NAME + "/" + _strip_right(test, ".java"),
+            native.package_name() + "/" + _strip_right(test, ".java"),
         )
         package = java_class[:java_class.rfind(".")]
         native.java_test(