Multiple service bindings

[philippthun]

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[philippthun]

With this change applied and max_service_credential_bindings_per_app_service_instance set to something >1, multiple bindings can be created between the same app and service instance - the newest is available in the app's environment variables. Here's an example:

$ cf create-app bommel
...

$ cf app bommel --guid
df4e2eb4-ffd2-4217-8965-2845cbec3233

$ cf create-user-provided-service bommel
...

$ cf service bommel --guid
afcf0417-f3ae-40d8-a913-fee00ad87af5

$ cf bind-service bommel bommel
...

$ cf curl '/v3/apps/df4e2eb4-ffd2-4217-8965-2845cbec3233/env'
...
  "binding_guid": "9983440a-813d-40d9-9592-a7a692cb0da3",
...

$ cf curl -X POST "/v3/service_credential_bindings" -d '{
    "type": "app",
    "strategy": "multiple",
    "relationships": {
      "service_instance": {
        "data": {
          "guid": "afcf0417-f3ae-40d8-a913-fee00ad87af5"
        }
      },
      "app": {
        "data": {
          "guid": "df4e2eb4-ffd2-4217-8965-2845cbec3233"
        }
      }
    }
  }'
...

$ cf curl '/v3/apps/df4e2eb4-ffd2-4217-8965-2845cbec3233/env'
...
  "binding_guid": "7ebce5c5-e683-4f8e-9c34-8e89e959d5c3"
...

[johha]

LGTM