Clean up the semantics of package descriptions.

test/upgrade/git/upgrade_to_nonexistent_pubspec_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // 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 pub_tests;
 
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
@@ skipping 13 matching lines @@
     d.dir(packagesPath, [
       d.dir('foo', [
         d.file('foo.dart', 'main() => "foo";')
       ])
     ]).validate();
 
     repo.runGit(['rm', 'pubspec.yaml']);
     repo.runGit(['commit', '-m', 'delete']);
 
     pubUpgrade(error: new RegExp(r'Could not find a file named "pubspec.yaml" '
-        r'in "[^\n]*"\.'));
+        r'in [^\n]*\.'));
 
     d.dir(packagesPath, [
       d.dir('foo', [
         d.file('foo.dart', 'main() => "foo";')
       ])
     ]).validate();
   });
 }