Merged a fix to tmpdir creation, so the gwt-tmp layer can't create 
permission errors

Review by: scottb
Merge from: 1.6@4498


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@4499 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/dev/core/src/com/google/gwt/util/tools/Utility.java b/dev/core/src/com/google/gwt/util/tools/Utility.java
index ed1d59c..4ed188b 100644
--- a/dev/core/src/com/google/gwt/util/tools/Utility.java
+++ b/dev/core/src/com/google/gwt/util/tools/Utility.java
@@ -253,7 +253,7 @@
   public static File makeTemporaryDirectory(File baseDir, String prefix)
       throws IOException {
     if (baseDir == null) {
-      baseDir = new File(System.getProperty("java.io.tmpdir"), GWT_TMP_DIR);
+      baseDir = new File(System.getProperty("java.io.tmpdir"));
     }
     baseDir.mkdirs();