message: centos image: yum install bc
  This is needed by the coverage build.
  Fixes
diff: @@ -10,7 +10,7 @@ curl -L -o /etc/yum.repos.d/alonid-llvm-5.0.0-epel-7.repo \
  # dependencies for bazel and build_recipes
  yum install -y java-1.8.0-openjdk-devel unzip which openssl rpm-build \
  cmake3 devtoolset-4-gcc-c++ git golang libtool make patch rsync wget \
  - clang-5.0.0 devtoolset-4-libatomic-devel llvm-5.0.0 python-virtualenv
  + clang-5.0.0 devtoolset-4-libatomic-devel llvm-5.0.0 python-virtualenv bc
  yum clean all
  ln -s /usr/bin/cmake3 /usr/bin/cmake
  