CI: set enterprise as test default (DE-1046)

Author: rashtao

.circleci/config.yml

@@ -23,7 +23,7 @@ commands:
     parameters:
       docker-img:
         type: 'string'
-        default: 'docker.io/arangodb/arangodb:latest'
+        default: 'docker.io/arangodb/enterprise:latest'
       topology:
         type: 'string'
         default: 'single'
@@ -82,7 +82,7 @@ jobs:
     parameters:
       docker-img:
         type: 'string'
-        default: 'docker.io/arangodb/arangodb:latest'
+        default: 'docker.io/arangodb/enterprise:latest'
       topology:
         type: 'string'
         default: 'single'