Lower the logging level for NATS messages to debug.
Don't log message fields that may contain passwords.
Return 204 (NO CONTENT) instead of 409 (CONFLICT) when the same build pack bits are uploaded.  Its not an error but an optimization that is OK.
Fixed spec to ignore both info and debug level logging.
Update catalog, plan, service validation errors

[Finishes #62854062]
Add default value for maximum_app_disk

We want to decouple dependency of cloud controller on cf-release. So
there should be a reasonable default value in CC.

[#64174044]

Signed-off-by: Maria Shaldibina <mariash@pivotallabs.com>
remove non-functional document_api
Change the error for non-unique service labels to match the desired error.

- the story specifies a desired error to return when trying to add
  services with the same label.
- uses rescue-less method for updating service label
- ensures uniqueness of label field for v2 services

[#63093570]
Reduces possible test pollution from fake servers

- adds at_exit hooks to specs that run fake service brokers
- finds and kills existing fake broker processes on start

[finishes #64709132]
Added tests for scrubbing senstive fields.
/v2/services can be filtered by label and provider

[#63185416]
Do not export system_env_json with get /v2/app/:guid response [finishes #55332776]
Add 'purge' parameter to DELETE /v2/services/:guid

A delete request with the param purge=true will delete the service and
its service plans, service instances, service bindings and service plan
visibilities. The service broker will not be contacted for service
instance or binding deletes.

Due to our reliance on before_destroy and after_destroy hooks to enforce
business logic, we were not comfortable doing a Sequel::Model#delete on
each record. Instead, we set the "purged" field on the services model to
true, which replaces the service broker client with a null object. This
ensures that we do not send requests to the broker, but still executes
all before_destroy and after_destroy logic.

[#63185416]
Merge remote-tracking branch 'origin/master' into services-fork

Conflicts:
  lib/cloud_controller/config.rb
  spec/config_spec.rb
  spec/fixtures/config/minimal_config.yml
Allow a buildpack to be locked
Expose the build pack key
Keep track of the filename so the admin knows what was uploaded
Adds endpoint for bulk updating service instances

- only allows the service_plan_guid as an updatable attribute

[#63080352]
Refactors ServiceInstance controller internals
Merge remote-tracking branch 'origin/master' into services-fork
Break out upload_bits
Remove exported key