Remove more libraries directives from server

pkg/analysis_server/lib/src/utilities/average.dart

Index: pkg/analysis_server/lib/src/utilities/average.dart
diff --git a/pkg/analysis_server/lib/src/utilities/average.dart b/pkg/analysis_server/lib/src/utilities/average.dart
index a20ad8887cb77f73c6c83b643dcd742fc3461096..22cf299b55beb03bd26cfaa92212dcb28c54bfa5 100644
--- a/pkg/analysis_server/lib/src/utilities/average.dart
+++ b/pkg/analysis_server/lib/src/utilities/average.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-library analysis_server.src.utilities.average;
-
 /// Simple rolling average sample counter.
 class Average {
   num _val;