convert: delete empty directories if deleting a file (bug 754)

hgext/convert/hg.py

@@ -31,7 +31,7 b' class convert_mercurial(converter_sink):'
 
     def delfile(self, f):
         try:
-            os.unlink(self.repo.wjoin(f))
+            util.unlink(self.repo.wjoin(f))
             #self.repo.remove([f])
         except:
             pass