Fixed an error in the export example.

Eddie Satterly found that when you run it twice without telling it to recover, it doesn't die when it should
throw an error about not recovering and not overwriting, but that gets clobbered by a later error where
open mode didn't get set properly.

Author: Frederick Ross

examples/export/export.py

@@ -329,7 +329,7 @@ def main():
 
     if path.exists(options.kwargs['output']):
         if options.kwargs['recover'] == False:
-            error("Export file exists, and recover option nor specified")
+            error("Export file %s exists, and recover option nor specified" % options.kwargs['output'], exitcode=1)
         else:
             options.kwargs['end'] = recover(options)
             options.kwargs['fixtail'] = True

utils/cmdopts.py

@@ -23,7 +23,7 @@
 # Print the given message to stderr, and optionally exit
 def error(message, exitcode = None):
     print >> sys.stderr, "Error: %s" % message
-    if not exitcode is None: sys.exit(exitcode)
+    if exitcode is not None: sys.exit(exitcode)
 
 class record(dict):
     def __getattr__(self, name):