Fetch and run get-helm script in two steps

Sometimes curl times out but that did not fail the job; now it will.

Signed-off-by: Lott, Christopher (cl778h) <cl778h@att.com>
Change-Id: I64ca83aa7d76a455a141036ab0144a88db8050ce
diff --git a/ci/Dockerfile b/ci/Dockerfile
index bd60013..cd5ad00 100644
--- a/ci/Dockerfile
+++ b/ci/Dockerfile
@@ -18,7 +18,9 @@
 
 FROM ubuntu:18.04
 RUN apt-get update && apt-get -y install curl
-RUN curl -L https://git.io/get_helm.sh | bash
+ARG GH=get_helm.sh
+RUN curl --silent --show-error -L https://git.io/${GH} -o ${GH}
+RUN bash ${GH}
 RUN helm init -c
 ARG TGT=/tmp/it-dep
 COPY . $TGT