[skip ci] Remove base image for jupyter/notebook

See https://github.com/jupyter/notebook/pull/1553

(c) Copyright IBM Corp. 2016

internal/ubuntu_14_04_locale_fix/Dockerfile

-FROM ubuntu:14.04
-
-# Setting the language and encoding won't work without this tweak.
-# See bug here ( https://bugs.launchpad.net/ubuntu/+bug/920601 ).
-RUN DEBIAN_FRONTEND=noninteractive locale-gen en_US.UTF-8 && \
-    DEBIAN_FRONTEND=noninteractive dpkg-reconfigure locales

internal/ubuntu_14_04_locale_fix/Makefile

-# Copyright (c) Jupyter Development Team.
-# Distributed under the terms of the Modified BSD License.
-
-.PHONY: build help release
-
-REPO:=jupyter/ubuntu_14_04_locale_fix
-
-help:
-	@echo 'make build release'
-	@echo 'See https://github.com/jupyter/docker-stacks/pull/108'
-
-build: DARGS?=
-build:
-	docker build $(DARGS) --rm --force-rm -t $(REPO):latest .
-
-release:
-	docker push $(REPO):latest

internal/ubuntu_14_04_locale_fix/README.md

-The Dockerfile in this folder serves as a base image for the `jupyter/notebook` image which comes from the master branch of https://github.com/jupyter/notebook. It's not used in the stacks here. See https://github.com/jupyter/docker-stacks/pull/108 for why it exists.