use bash AND (&&) instead of command-separator (;) on docker images

Otherwise, image build phases yield images even though there may be
erros in the build process.

For example, the following image is built however there is a command
that fails (false command)

    echo -e 'FROM ubuntu:bionic\nRUN false; true' | docker build -
    Sending build context to Docker daemon  2.048kB
    Step 1/2 : FROM ubuntu:bionic
     ---> 56def654ec22
    Step 2/2 : RUN false; true
     ---> Running in 85759437ee6b
    Removing intermediate container 85759437ee6b
     ---> 44ee5447fd5d
    Successfully built 44ee5447fd5d

versus this image that fails (correctly) due to errors

    echo -e 'FROM ubuntu:bionic\nRUN false && true' | docker build -
    Sending build context to Docker daemon  2.048kB
    Step 1/2 : FROM ubuntu:bionic
     ---> 56def654ec22
    Step 2/2 : RUN false && true
     ---> Running in f4b9ac94bf12
    The command '/bin/sh -c false && true' returned a non-zero code: 1

Signed-off-by: Leonardo Sandoval <leonardo.sandoval@linaro.org>
Change-Id: Iea48194869c884fc6d3d6c64a1fd6ea7be41ec84
4 files changed