Use python3 when present

Some newer images include python3 but not python. This change will
alias python to python3 when the executable is found.

Change-Id: I752a265c67887b6e6b2389bf4009bdbf8e2aed09

elasticsearch/Chart.yaml

@@ -15,7 +15,7 @@ apiVersion: v1
 appVersion: v7.6.2
 description: OpenStack-Helm ElasticSearch
 name: elasticsearch
-version: 0.2.15
+version: 0.2.16
 home: https://www.elastic.co/
 sources:
   - https://github.com/elastic/elasticsearch

elasticsearch/templates/bin/_helm-tests.sh.tpl

@@ -15,6 +15,10 @@ limitations under the License.
 
 set -ex
 
+if [[ $(which python3) ]]; then
+    alias python=python3
+fi
+
 function create_test_index () {
   index_result=$(curl ${CACERT_OPTION} -K- <<< "--user ${ELASTICSEARCH_USERNAME}:${ELASTICSEARCH_PASSWORD}" \
   -XPUT "${ELASTICSEARCH_ENDPOINT}/test_index?pretty" -H 'Content-Type: application/json' -d'

releasenotes/notes/elasticsearch.yaml

@@ -25,4 +25,5 @@ elasticsearch:
   - 0.2.13 Update htk requirements
   - 0.2.14 Fix cronjob rendering
   - 0.2.15 Fix elasticsearch-data shutdown
+  - 0.2.16 Use python3 for helm tests when possible
 ...