egeria: Asset Catalog OMAS - exception on supportedTypes (impacts UI)

The UI hits an exception on startup. The console logs (debug enabled) show:

2020-01-16 09:23:34.313 ERROR 37799 --- [nio-8443-exec-5] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is PropertyServerException{reportedHTTPCode=503, reportingClassName='org.odpi.openmetadata.accessservices.assetcatalog.AssetCatalog', reportingActionDescription='getSupportedTypes', errorMessage='OMAG-COMMON-503-001 A client-side exception was received from API call getSupportedTypes to OMAG Server cocoMDS4 at http://localhost:8081.  The error message was CLIENT-SIDE-REST-API-CONNECTOR-503-002 A client-side exception org.springframework.web.client.HttpServerErrorException$InternalServerError was received by method getSupportedTypes from API call http://localhost:8081/servers/{0}/open-metadata/access-services/asset-catalog/users/{1}/supportedTypes?type={2} to server cocoMDS4 on platform http://localhost:8081.  The error message was 500 : [{"timestamp":"2020-01-16T09:23:34.262+0000","status":500,"error":"Internal Server Error","message":"No message available","path":"/servers/cocoMDS4/open-metadata/access-services/asset-catalog/users/faithbroker/supportedTypes"}]', reportedSystemAction='The server has issued a call to the open metadata access service REST API in a remote server and has received an exception from the local client libraries.', reportedUserAction='Look for errors in the local server's console to understand and correct the source of the error.', reportedCaughtException=RESTServerException{reportedHTTPCode=503, reportingClassName='org.odpi.openmetadata.adapters.connectors.restclients.spring.SpringRESTClientConnector', reportingActionDescription='getSupportedTypes', errorMessage='CLIENT-SIDE-REST-API-CONNECTOR-503-002 A client-side exception org.springframework.web.client.HttpServerErrorException$InternalServerError was received by method getSupportedTypes from API call http://localhost:8081/servers/\{0\}/open-metadata/access-services/asset-catalog/users/\{1\}/supportedTypes\?type\=\{2\} to server cocoMDS4 on platform http://localhost:8081.  The error message was 500 : [{"timestamp":

Furthermore, an attempt to invoke this endpoint from the cli also fails with 500

✗ http GET http://localhost:8081/servers/cocoMDS4/open-metadata/access-services/asset-catalog/users/faithbroker/supportedTypes
HTTP/1.1 500
Connection: close
Content-Type: application/json
Date: Thu, 16 Jan 2020 09:38:00 GMT
Transfer-Encoding: chunked

{
    "error": "Internal Server Error",
    "message": "No message available",
    "path": "/servers/cocoMDS4/open-metadata/access-services/asset-catalog/users/faithbroker/supportedTypes",
    "status": 500,
    "timestamp": "2020-01-16T09:38:00.415+0000"
}

Originally noted in #2426