Add new fields to ServiceErrorResponse
Remove GatewayExternalError

This exception was never handled any differently than a standard
ErrorResponse.

[#55121498]
Ensure service errors include new fields
Move service error info to an error hash
Support for ssl service gateways.
Bump cf-message-bus, stringify keys
Symbolize kyes in `config` before accessing it
Merge pull request #8 from yudai/request/symbolize_keys_config

Symbolize kyes in `config` before accessing it

@ryantang / @xoebus
Increase EM timeout for discovery messages test
added new license
Merge pull request #7 from youngm/master

Support for ssl service gateways

* Confirmed that this worked when we bumped this gem on CC as well as an internal broker that we use for our marketplace on run.pivotal.io.

@ryantang / @xoebus