hg2git.py: Fix typo saving status to headsfile instead of statusfile

This broke incremental imports as hg2git.sh wrapper overwrites headsfile
with current values after the import is done.

Signed-off-by: Rocco Rutte <pdmef@gmx.net>

hg2git.py

@@ -374,4 +374,4 @@ if __name__=='__main__':
   if options.marksfile==None: bail(parser,'--repo')
 
   sys.exit(hg2git(options.repourl,m,options.marksfile,options.headsfile,
-    options.headsfile,sob=options.sob))
+    options.statusfile,sob=options.sob))