Properly report pub.dartlang.org API errors.

sdk/lib/_internal/pub/lib/src/http.dart

Index: sdk/lib/_internal/pub/lib/src/http.dart
diff --git a/sdk/lib/_internal/pub/lib/src/http.dart b/sdk/lib/_internal/pub/lib/src/http.dart
index f9e63bbb8590eb0eb5f95e8130a1932d1b80514b..7108b255860f1dcf21d1fba72375c375f7950194 100644
--- a/sdk/lib/_internal/pub/lib/src/http.dart
+++ b/sdk/lib/_internal/pub/lib/src/http.dart
@@ -99,8 +99,6 @@ class PubHttpClient extends http.BaseClient {
               '"${request.url.origin}".');
         }
       }
-      print('Error in PubHttpClient.send (issue 12581) error: $error');
-      print('    stacktrace: $stackTrace');
       throw error;
     }), HTTP_TIMEOUT, 'fetching URL "${request.url}"');
   }
@@ -197,7 +195,7 @@ void handleJsonError(http.Response response) {
       errorMap['error']['message'] is! String) {
     invalidServerResponse(response);
   }
-  throw errorMap['error']['message'];
+  fail(errorMap['error']['message']);
 }
 
 /// Parses a response body, assuming it's JSON-formatted. Throws a user-friendly