install-deps.sh: exit on error if dependencies cannot be installed

install-deps.sh: exit on error if dependencies cannot be installed

Now that pre-installing pip dependencies is done at the end of the
script, the last command to run is no longer the installation
command. Therefore the status of the script is no longer the status of
the install command and no longer reflect success or failure to install
the dependencies. Add explicit || exit 1 to commands that are to be
treated as fatal errors.

Also set -e so that another error has a better chance to be caught.

Signed-off-by: Loic Dachary <ldachary@redhat.com>