Make useradd line a little less clever

Author: JoshMock

.buildkite/Dockerfile

@@ -11,7 +11,7 @@ RUN apt-get clean -y && \
 
 # Set up all files as owned by non-root user
 RUN groupadd -f --system -g ${BUILDER_GROUP} elastic \
-    && (id -u ${BUILDER_USER} 2>&1 /dev/null || useradd --system --shell /bin/bash -u ${BUILDER_USER} -g ${BUILDER_GROUP} -m elastic 2>&1 /dev/null) \
+    && (id -u ${BUILDER_USER} || useradd --system --shell /bin/bash -u ${BUILDER_USER} -g ${BUILDER_GROUP} -m elastic) \
     && mkdir -p /usr/src/app \
     && chown -R ${BUILDER_USER}:${BUILDER_GROUP} /usr/src/ \
     && mkdir -p /.npm \