Cleanup after Miniconda install in Docker build

To cutdown on the Docker image size, handle the install of Miniconda and
subsequent clean up in the same `RUN` step. The cleanup includes the
removal the install script, cached conda packages, and conda package
tarballs. This should cutdown the size of this Docker layer and save
memory on CI.

Dockerfile-master

@@ -4,8 +4,10 @@ ENV LANG C.UTF-8
 
 RUN apt-get update && apt-get install curl bzip2 git gcc -y --fix-missing
 
-RUN curl -o miniconda.sh https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh
-RUN bash miniconda.sh -f -b -p /opt/anaconda
+RUN curl -o miniconda.sh https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh && \
+    bash miniconda.sh -f -b -p /opt/anaconda && \
+    /opt/anaconda/bin/conda clean -tipy && \
+    rm -f miniconda.sh
 ENV PATH /opt/anaconda/bin:$PATH
 RUN conda install -n root conda=4.4.11 && conda clean -tipy
 RUN conda install -c conda-forge dask distributed nomkl pytest mock ipython pip psutil && conda clean -tipy

Dockerfile-slave

@@ -4,7 +4,10 @@ ENV LANG C.UTF-8
 
 RUN apt-get update && apt-get install curl bzip2 git gcc -y --fix-missing
 
-RUN curl -o miniconda.sh https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh
+RUN curl -o miniconda.sh https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh && \
+    bash miniconda.sh -f -b -p /opt/anaconda && \
+    /opt/anaconda/bin/conda clean -tipy && \
+    rm -f miniconda.sh
 RUN bash miniconda.sh -f -b -p /opt/anaconda
 ENV PATH /opt/anaconda/bin:$PATH
 RUN conda install -n root conda=4.4.11 && conda clean -tipy