Tidy up bundle_firmware to stand alone

This removes bundle_firmware's dependence on a parser option for its
configuration.

BUG=chromium-os:17753
TEST=manual: ~/trunk/src/platform/dev/host/cros_bundle_firmware -w

Change-Id: I5d2f18547d518823d59f8fd1c291c62a773a5917
Reviewed-on: http://gerrit.chromium.org/gerrit/4344
Reviewed-by: Che-Liang Chiou <clchiou@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
diff --git a/host/lib/tools.py b/host/lib/tools.py
index ff9911f..586f5a6 100755
--- a/host/lib/tools.py
+++ b/host/lib/tools.py
@@ -36,7 +36,12 @@
   """A class to encapsulate the external tools we want to run
 
   This provides convenient functions for running tools inside/outside the
-  chroot. It also provides common paths:
+  chroot.
+
+  Public properties:
+    outdir: The output directory to write output files to.
+
+  The tools class also provides common paths:
 
     chroot_path: chroot directory
     src_path: source directory
@@ -271,6 +276,8 @@
     else:
       self.outdir = tempfile.mkdtemp()
       self._delete_tempdir = self.outdir
+      self._out.Debug("Using temporary directory '%s'" %
+          self._delete_tempdir)
 
   def FinalizeOutputDir(self):
     """Tidy up the output direcory, deleting it if temporary"""