message: install scikit-learn for pip builds.
diff: @@ -257,7 +257,7 @@ PYTHON_BIN_PATH_INIT=${PYTHON_BIN_PATH}
  PIP_BIN_PATH="$(which pip${PY_MAJOR_MINOR_VER})"
  # PIP packages
  -INSTALL_EXTRA_PIP_PACKAGES="portpicker scipy ${TF_BUILD_INSTALL_EXTRA_PIP_PACKAGES}"
  +INSTALL_EXTRA_PIP_PACKAGES="portpicker scipy scikit-learn ${TF_BUILD_INSTALL_EXTRA_PIP_PACKAGES}"
  ###########################################################################
  # Build TF PIP Package
  