Ensure e2e tests run if optional deps are missing (cloudfoundry#4921)

* Don't fail job-e2e-before_script script if s3 server is missing

* Fix helm v2 cli install
- Peg to lastest v2 build
- Script fails to automatically find it
  - grep of helm release page fails to find 'v2' in first page returned by github

deploy/ci/travis/helm-chart-unit-tests.sh

@@ -8,7 +8,7 @@ echo "============================="
 echo "Installing Helm"
 curl https://raw.githubusercontent.com/helm/helm/master/scripts/get > get_helm.sh
 chmod 700 get_helm.sh
-./get_helm.sh
+./get_helm.sh -v v2.17.0 # peg to lastest v2 build (script fails to automatically find it - grep of helm release page fails to find v2 in first page)
 
 echo "Helm Init (Client)"
 helm init --client-only

deploy/ci/travis/job-e2e-before_script.sh

@@ -21,9 +21,10 @@ docker run -d -p 8080:8080 splatform/stratos-uaa
 
 # Check that the S3 server is available
 if [ -n "${AWS_ENDPOINT}" ]; then
+  set +e
   curl -k --max-time 20 ${AWS_ENDPOINT}
   if [ $? -ne 0 ]; then
     echo "Can not contact S3 Server"
-    exit 1
+    exit 0 # Don't fail whole run if the server is unavailable
   fi
 fi