make sure that the base directory exists first.

See http://www.nabble.com/ClearCase-plugin-0.2-not-working-with-1.160-tf4948031.html


git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@6220 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/FilePath.java

@@ -445,6 +445,8 @@ public final class FilePath implements Serializable {
                 public String invoke(File dir, VirtualChannel channel) throws IOException {
                     if(!inThisDirectory)
                         dir = null;
+                    else
+                        dir.mkdirs();
                     File f = File.createTempFile(prefix, suffix, dir);
 
                     Writer w = new FileWriter(f);