tast: Update generate_metadata.py due to proto file location change

Update generate_metadata.py due to proto file location change

BUG=b:193583192
TEST=python3.6 ./generate_metadata.py -output_file=test,generate_metadata_unittest

Cq-Depend: chromium:3024842
Cq-Depend: chromium:3026065
Change-Id: Iff1d5c82aa904d3e1bc8db15bf577d2409cf08cc
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/3026129
Tested-by: Seewai Fu <seewaifu@google.com>
Reviewed-by: Derek Beckett <dbeckett@chromium.org>
Reviewed-by: C Shapiro <shapiroc@chromium.org>
Commit-Queue: Seewai Fu <seewaifu@google.com>
diff --git a/utils/generate_metadata.py b/utils/generate_metadata.py
index 4c246b2..78c5622 100644
--- a/utils/generate_metadata.py
+++ b/utils/generate_metadata.py
@@ -21,8 +21,8 @@
 from autotest_lib.server.cros.dynamic_suite import control_file_getter
 from autotest_lib.client.common_lib import control_data
 
-from chromiumos.test.internal import test_case_metadata_pb2 as tc_metadata_pb
-from chromiumos.test.internal import test_harness_pb2 as th_pb
+from chromiumos.test.api import test_case_metadata_pb2 as tc_metadata_pb
+from chromiumos.test.api import test_harness_pb2 as th_pb
 from chromiumos.test.api import test_case_pb2 as tc_pb
 
 HARNESS = th_pb.TestHarness.Tauto()