Set default deployment settings to aws

playbooks/roles/mlapi/vars/main.yml

@@ -2,7 +2,7 @@ mlapi_source_repo: git@github.com:edx/ml-service-api.git
 ml_source_repo: git@github.com:edx/machine-learning.git
 ml_dir: $app_base_dir/machine-learning
 ml_api_dir: $app_base_dir/ml-service-api
-ml_api_settings: ml_service_api.settings
+ml_api_settings: ml_service_api.aws
 nltk_data_dir: /usr/share/nltk_data
 remote_user: ubuntu
 ml_branch: master