Delete Bazel BUILD overlay for kws streaming (#5909)

This is no longer used as we no longer support a Bazel build for the
Python bindings.

build_tools/third_party/kws_streaming/BUILD.overlay

diff --git a/build_tools/third_party/kws_streaming/BUILD.overlay b/build_tools/third_party/kws_streaming/BUILD.overlay
deleted file mode 100644
index eeac705..0000000
--- a/build_tools/third_party/kws_streaming/BUILD.overlay
+++ /dev/null
@@ -1,120 +0,0 @@
-# Copyright 2020 Google LLC
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      https://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-package(
-    default_visibility = ["//visibility:public"],
-)
-
-py_library(
-    name = "train_lib",
-    srcs = [
-        "train/base_parser.py",
-        "train/test.py",
-        "train/train.py",
-    ],
-    srcs_version = "PY3",
-    deps = [
-        ":input_data_lib",
-        ":models_lib",
-    ],
-)
-
-py_library(
-    name = "models_lib",
-    srcs = [
-        "models/att_mh_rnn.py",
-        "models/att_rnn.py",
-        "models/cnn.py",
-        "models/crnn.py",
-        "models/dnn.py",
-        "models/dnn_raw.py",
-        "models/ds_cnn.py",
-        "models/ds_tc_resnet.py",
-        "models/gru.py",
-        "models/inception.py",
-        "models/inception_resnet.py",
-        "models/lstm.py",
-        "models/mobilenet.py",
-        "models/mobilenet_v2.py",
-        "models/model_flags.py",
-        "models/model_params.py",
-        "models/models.py",
-        "models/svdf.py",
-        "models/svdf_resnet.py",
-        "models/tc_resnet.py",
-        "models/utils.py",
-        "models/xception.py",
-    ],
-    srcs_version = "PY3",
-    deps = [
-        ":input_data_lib",
-        ":layers_compat",
-        ":layers_lib",
-    ],
-)
-
-py_library(
-    name = "input_data_lib",
-    srcs = ["data/input_data.py"],
-    srcs_version = "PY3",
-    deps = [
-        ":layers_lib",
-    ],
-)
-
-py_library(
-    name = "layers_lib",
-    srcs = [
-        "layers/contrib_conv2d.py",
-        "layers/conv1d_transpose.py",
-        "layers/data_frame.py",
-        "layers/dct.py",
-        "layers/delay.py",
-        "layers/depthwise_conv1d.py",
-        "layers/gru.py",
-        "layers/lstm.py",
-        "layers/magnitude_rdft.py",
-        "layers/magnitude_rdft_mel.py",
-        "layers/mel_spectrogram.py",
-        "layers/mel_table.py",
-        "layers/modes.py",
-        "layers/non_scaling_dropout.py",
-        "layers/normalizer.py",
-        "layers/preemphasis.py",
-        "layers/random_shift.py",
-        "layers/random_stretch_squeeze.py",
-        "layers/spectrogram_augment.py",
-        "layers/spectrogram_cutout.py",
-        "layers/speech_features.py",
-        "layers/stream.py",
-        "layers/svdf.py",
-        "layers/temporal_padding.py",
-        "layers/windowing.py",
-    ],
-    srcs_version = "PY3",
-    deps = [
-        ":layers_compat",
-        "@absl_py//absl/logging",
-    ],
-)
-
-py_library(
-    name = "layers_compat",
-    srcs = ["layers/compat.py"],
-    srcs_version = "PY3",
-    deps = [
-        "@absl_py//absl/flags",
-        "@absl_py//absl/logging",
-    ],
-)