downgrade elasticsearch to fit inventaire requirements

docker-compose.yml

@@ -20,10 +20,11 @@ services:
       - ./utils/config/inventaire-local.coffee:/opt/inventaire/config/local.coffee
     working_dir: /opt/inventaire
     depends_on:
-      - couch
       - entities-search-engine
+      - couch
+      - elasticsearch
   elasticsearch:
-    image: elasticsearch
+    image: elasticsearch:2.4
     environment:
       - 'http.host=0.0.0.0'
       - 'transport.host=127.0.0.1'
@@ -40,6 +41,4 @@ services:
     volumes:
       - ./entities-search-engine:/opt/entities-search-engine
       - ./utils/config/entities-search-engine-local.coffee:/opt/entities-search-engine/config/local.coffee
-    links:
-      - couch
     working_dir: /opt/entities-search-engine