message: CI: Fix image.
diff: FROM ubuntu:18.10 AS cosmic-ci
  -RUN apt-get update && apt-get install -y ccache fuse git python3.5 python3-pip valgrind && rm -rf /var/lib/apt/lists/*
  +RUN apt-get update && apt-get install -y ccache fuse git gnutls-bin python3.5 python3-pip valgrind && rm -rf /var/lib/apt/lists/*
  +RUN ln -s /usr/lib/x86_64-linux-gnu/libgnutls.so.30 /usr/lib/x86_64-linux-gnu/libgnutls.so
  ADD drake/requirements.txt .
  RUN pip3 install -r requirements.txt
  