No longer install notebook/jupyterhub packages on Python 3.5

now that it's a kernel-only environment

repo2docker/buildpacks/conda/requirements.py-3.5.pip

@@ -1,17 +0,0 @@
-# pip-installed packages for Python 3.5
-# these should only be packages
-# whose versions are too new to have builds available for Python 3.5
-alembic==1.0.3
-async-generator==1.10
-chardet==3.0.4
-idna==2.7
-jupyterhub==0.9.4
-mako==1.0.7
-notebook==5.7.8
-nteract-on-jupyter==1.9.6
-pamela==0.3.0
-python-editor==1.0.3
-python-oauth2==1.1.0
-requests==2.20.1
-sqlalchemy==1.2.14
-urllib3==1.24.1