tensorflow: drop 1.x

it no longer works without our default python version and needs
many patches to compile.

pkgs/development/python-modules/tensorflow-estimator/1/default.nix

@@ -1,30 +0,0 @@
-{ stdenv, fetchPypi, buildPythonPackage
-, numpy
-, absl-py
-, mock
-}:
-
-buildPythonPackage rec {
-  pname = "tensorflow-estimator";
-  # This is effectively 1.15.0. Upstream tagged 1.15.0 by mistake before
-  # actually updating the version in setup.py, which is why this tag is called
-  # 1.15.1.
-  version = "1.15.1";
-  format = "wheel";
-
-  src = fetchPypi {
-    pname = "tensorflow_estimator";
-    inherit version format;
-    sha256 = "1fc61wmc0w22frs79j2x4g6wnv5g21xc6rix1g4bsvy9qfvvylw8";
-  };
-
-  propagatedBuildInputs = [ mock numpy absl-py ];
-
-  meta = with stdenv.lib; {
-    description = "TensorFlow Estimator is a high-level API that encapsulates model training, evaluation, prediction, and exporting.";
-    homepage = "http://tensorflow.org";
-    license = licenses.asl20;
-    maintainers = with maintainers; [ jyp ];
-  };
-}
-