message: Dockerfile: build and install gRPC and protobuf
  This updates the build and install steps according to the README.
diff: @@ -25,31 +25,40 @@ RUN apt-get update \
  automake \
  python \
  python-pip \
  - software-properties-common \
  && apt-get -y autoremove \
  && apt-get clean autoclean \
  && rm -rf /var/lib/apt/lists/{apt,dpkg,cache,log} /tmp/* /var/tmp/*
  -RUN add-apt-repository ppa:maarten-fonville/protobuf \
  - && apt-get update \
  - && apt-get -y --quiet --no-install-recommends install \
  - protobuf-compiler \
  - libprotobuf-dev \
  - && apt-get clean autoclean \
  - && rm -rf /var/lib/apt/lists/{apt,dpkg,cache,log} /tmp/* /var/tmp/*
  -
  RUN pip install grpcio grpcio-tools
  -# Install grpc according to https://github.com/grpc/grpc/blob/v1.6.x/INSTALL.md
  +# Install gRPC according to https://github.com/grpc/grpc/blob/v1.6.x/INSTALL.md
  # And to fix build error https://github.com/grpc/grpc/issues/12316
  +# Install gRPC and protobuf into /opt in order not to mess up the host system.
  +# Also, we need to patch the Makefile because it install the libraries with
  +# wrong versions.
  +
  +RUN mkdir /opt/grpc && chown $USER:$USER /opt/grpc
  +RUN mkdir /opt/protobuf && chown $USER:$USER /opt/protobuf
  +
  +ADD grpc/0001-Makefile-fix-wrong-SHARED-version-suffix.patch 0001-Makefile-fix-wrong-SHARED-version-suffix.patch
  +
  RUN git clone -b v1.6.x https://github.com/grpc/grpc \
  && cd grpc \
  && git submodule update --init \
  + && git apply ../0001-Makefile-fix-wrong-SHARED-version-suffix.patch \
  && make -j8 HAS_SYSTEM_PROTOBUF=false \
  + && make prefix=/opt/grpc install \
  + && cd third_party/protobuf \
  + && make clean \
  + && ./configure --prefix=/opt/protobuf \
  + && make -j8 \
  && make install \
  - && cd .. \
  + && cd ../../.. \
  && rm -rf grpc
  +ENV GRPC_DIR=/opt/grpc
  +ENV PROTOBUF_DIR=/opt/protobuf
  +
  CMD ["/bin/bash"]
  WORKDIR "/home/docker1000/src/DroneCore"
  