errdefs: remove unneeded recursive calls

The `statusCodeFromGRPCError` and `statusCodeFromDistributionError`
helpers are used by `GetHTTPErrorStatusCode`, which already recurses
if the error implements the `Causer` interface.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 32f4fdfb5c8846922302c20fdcab973227eb9bd6)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

errdefs/http_helpers.go

@@ -141,9 +141,6 @@ func statusCodeFromGRPCError(err error) int {
 	case codes.Unavailable: // code 14
 		return http.StatusServiceUnavailable
 	default:
-		if e, ok := err.(causer); ok {
-			return statusCodeFromGRPCError(e.Cause())
-		}
 		// codes.Canceled(1)
 		// codes.Unknown(2)
 		// codes.DeadlineExceeded(4)
@@ -168,10 +165,6 @@ func statusCodeFromDistributionError(err error) int {
 		}
 	case errcode.ErrorCoder:
 		return errs.ErrorCode().Descriptor().HTTPStatusCode
-	default:
-		if e, ok := err.(causer); ok {
-			return statusCodeFromDistributionError(e.Cause())
-		}
 	}
 	return http.StatusInternalServerError
 }