patman: Reset the output directory when it is removed

At present outdir remains set ever after the output directory has been
removed. Fix this to avoid trying to access it when it is not present.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/patman/tools.py

@@ -83,6 +83,7 @@ def FinaliseOutputDir():
     """Tidy up: delete output directory if temporary and not preserved."""
     if outdir and not preserve_outdir:
         _RemoveOutputDir()
+        outdir = None
 
 def GetOutputFilename(fname):
     """Return a filename within the output directory.
@@ -101,6 +102,7 @@ def _FinaliseForTest():
 
     if outdir:
         _RemoveOutputDir()
+        outdir = None
 
 def SetInputDirs(dirname):
     """Add a list of input directories, where input files are kept.