Remove develop dockerfile

docker/devel/Dockerfile

-# Dockerfile for Dgraph
-
-# For your convenience:
-#   docker build -t dgraph/devel .
-#   docker run -it dgraph/devel bash
-
-FROM golang:1.7
-MAINTAINER Dgraph Labs <contact@dgraph.io>
-
-# Get the necessary packages.
-RUN apt-get update && apt-get install -y --no-install-recommends \
-	wget \
-	git \
-	libbz2-dev \
-	libgflags-dev \
-	libsnappy-dev \
-	zlib1g-dev \
-	&& rm -rf /var/lib/apt/lists/*
-
-# Install and set up RocksDB.
-RUN mkdir /installs && cd /installs && \
-	git clone --branch v4.9 https://github.com/facebook/rocksdb.git
-RUN cd /installs/rocksdb && \
-	make shared_lib && \
-	make install
-
-# Install and set up ICU.
-RUN cd /installs && \
-	wget http://download.icu-project.org/files/icu4c/57.1/icu4c-57_1-src.tgz && \
-	tar xvzf icu4c-57_1-src.tgz
-RUN cd /installs/icu/source && \
-	./configure --disable-renaming && \
-	make && \
-	make install
-
-ENV LD_LIBRARY_PATH "/usr/local/lib"
-
-# Install Dgraph and update dependencies to right versions.
-# NOTE: Add -d to avoid building everything, which would include cockroachDB
-# stuff which we only need for embedding, and can take a long time and
-# potentially crash the build.
-RUN go get -v -d github.com/dgraph-io/dgraph/... && \
-	go build -v github.com/dgraph-io/dgraph/cmd/... && \
-	go install -v github.com/dgraph-io/dgraph/cmd/...
-	
-# TODO: Uncomment and enable tests after they pass.
-# RUN go test github.com/dgraph-io/dgraph/...
-
-# Mainly test out RocksDB and ICU.
-# RUN go test github.com/dgraph-io/dgraph/tok/...
-
-# Create the dgraph and data directory. These directories should be mapped
-# to host machine for persistence.
-RUN mkdir /dgraph && mkdir /data