fix relative @HtmlImport paths in deep folders in deployment mode

lib/build/html_import_annotation_recorder.dart

Index: lib/build/html_import_annotation_recorder.dart
diff --git a/lib/build/html_import_annotation_recorder.dart b/lib/build/html_import_annotation_recorder.dart
index 336ee7c2852601946a6686ffe962dc0c03f710b7..e517e33531194daeacba1093305c8da6b828d009 100644
--- a/lib/build/html_import_annotation_recorder.dart
+++ b/lib/build/html_import_annotation_recorder.dart
@@ -79,7 +79,7 @@ class HtmlImportAnnotationRecorder implements InitializerPlugin {
           path.url.joinAll(segments.getRange(1, segments.length)),
           from: path.url.dirname(path.url.join(bootstrapId.path)));
     } else if (segments[1] == 'lib') {
-      libPath = path.url.joinAll(segments.getRange(1, segments.length));
+      libPath = path.url.joinAll(segments.getRange(2, segments.length));
     } else {
       logger.error('Unable to import `${element.source.uri.path}` from '
           '${bootstrapId}.');