fix some minor issues in dockerfile (#165)

* fix some minor issues in dockerfile


RUN echo 'debconf debconf/frontend select Noninteractive' | debconf-set-selections
fixes
debconf: unable to initialize frontend: Dialog
debconf: (TERM is not set, so the dialog frontend is not usable.)
debconf: falling back to frontend: Readline
debconf: unable to initialize frontend: Readline
debconf: (This frontend requires a controlling tty.)
debconf: falling back to frontend: Teletype
dpkg-preconfigure: unable to re-open stdin: 

RUN apt-get update -y && apt-get install -y apt-utils
fixes
debconf: delaying package configuration, since apt-utils is not installed

* remove redundant command

* add -y to conda install and pip install

* remove -y from pip install

docker/Dockerfile

@@ -3,9 +3,11 @@ ARG CUDNN="7"
 
 FROM nvidia/cuda:${CUDA}-cudnn${CUDNN}-devel-ubuntu16.04
 
+RUN echo 'debconf debconf/frontend select Noninteractive' | debconf-set-selections
+
 # install basics
 RUN apt-get update -y \
- && apt-get install -y git curl ca-certificates bzip2 cmake tree htop bmon iotop g++
+ && apt-get install -y apt-utils git curl ca-certificates bzip2 cmake tree htop bmon iotop g++
 
 # Install Miniconda
 RUN curl -so /miniconda.sh https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh \
@@ -16,7 +18,7 @@ RUN curl -so /miniconda.sh https://repo.continuum.io/miniconda/Miniconda3-latest
 ENV PATH=/miniconda/bin:$PATH
 
 # Create a Python 3.6 environment
-RUN /miniconda/bin/conda install conda-build \
+RUN /miniconda/bin/conda install -y conda-build \
  && /miniconda/bin/conda create -y --name py36 python=3.6.7 \
  && /miniconda/bin/conda clean -ya
 
@@ -25,11 +27,11 @@ ENV CONDA_PREFIX=/miniconda/envs/$CONDA_DEFAULT_ENV
 ENV PATH=$CONDA_PREFIX/bin:$PATH
 ENV CONDA_AUTO_UPDATE_CONDA=false
 
-RUN conda install ipython
+RUN conda install -y ipython
 RUN pip install ninja yacs cython matplotlib
 
 # Install PyTorch 1.0 Nightly
-RUN conda install pytorch-nightly -c pytorch && conda clean -ya
+RUN conda install -y pytorch-nightly -c pytorch && conda clean -ya
 
 # Install TorchVision master
 RUN git clone https://github.com/pytorch/vision.git \