Fix version when a relative path is used.

tools/release/version.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.
 
 /**
  * This file contains functionality for getting dart version numbers using
  * our standard version construction method. Systems that does not include this
  * file should emulate the structure for revision numbers that we have here.
  *
  * The version number of a dart build is constructed as follows:
@@ skipping 131 matching lines @@
     }
     var isSvn = repositoryType == RepositoryType.SVN;
     var command = isSvn ? "svn" : "git";
     command = "$command${getExecutableSuffix()}";
     var arguments = isSvn ? ["info"] : ["svn", "info"];
     ProcessOptions options = new ProcessOptions();
     // Run the command from the root to get the last changed revision for this
     // "branch". Since we have both trunk and bleeding edge in the same
     // repository and since we always build TOT we need this to get the
     // right version number.
-    Path root =
-        new Path.fromNative(_versionFileName).directoryPath.directoryPath;
+    Path toolsDirectory = new Path.fromNative(_versionFileName).directoryPath;
+    Path root = toolsDirectory.join(new Path(".."));
     options.workingDirectory = root.toNativePath();
     return Process.run(command, arguments, options).transform((result) {
       if (result.exitCode != 0) {
         return 0;
       }
       return getRevisionFromSvnInfo(result.stdout);
     });
   }
 
   bool isProductionBuild(String username) {
@@ skipping 31 matching lines @@
   static RepositoryType guessType() {
     if (new Directory(".svn").existsSync()) return RepositoryType.SVN;
     if (new Directory(".git").existsSync()) return RepositoryType.GIT;
     return RepositoryType.UNKNOWN;
   }
 
   String toString() => name;
 
   final String name;
 }