Run elasticsearch in development mode for test builds

When elasticsearch is bound to localhost it runs in development mode. This mode makes a few startup checks of elasticsearch
less strict (they become warnings), allowing it to boot anyway.

On circleci its servers the value for  is too low and elasticsearch wont start. So we make sure we
are running in dev mode so we can at least run our tests

elastic/elasticsearch#4978 (comment)

circle.yml

@@ -1,7 +1,9 @@
 machine:
   php:
     version: 7.0.4
+  java:
+    version: openjdk8
 
 dependencies:
   pre:
-    - sh ./install-elasticsearch.sh
+    - sh ./install-elasticsearch.sh testing

install-elasticsearch.sh

@@ -20,7 +20,10 @@ rm elasticsearch-$ELASTICSEARCH_VERSION.deb
 sudo sed -i "s/#index.number_of_shards: 1/index.number_of_shards: 1/" /etc/elasticsearch/elasticsearch.yml
 sudo sed -i "s/#index.number_of_replicas: 0/index.number_of_replicas: 0/" /etc/elasticsearch/elasticsearch.yml
 sudo sed -i "s/#bootstrap.mlockall: true/bootstrap.mlockall: true/" /etc/elasticsearch/elasticsearch.yml
-sudo sed -i "s/#network.host: 192.168.0.1/network.host: 0.0.0.0/" /etc/elasticsearch/elasticsearch.yml
+if [ "$1" != "testing" ] ; then
+	echo ">>> Binding elasticsearch to all network hosts"
+	sudo sed -i "s/#network.host: 192.168.0.1/network.host: 0.0.0.0/" /etc/elasticsearch/elasticsearch.yml
+fi
 sudo service elasticsearch restart
 
 # Configure to start up Elasticsearch automatically