vfs: add removedirs

vfs: add removedirs

--- a/mercurial/scmutil.py	Sat Apr 11 00:47:09 2015 +0900
+++ b/mercurial/scmutil.py	Sat Apr 11 00:47:09 2015 +0900
@@ -316,6 +316,11 @@
     def readlink(self, path):
         return os.readlink(self.join(path))
 
+    def removedirs(self, path=None):
+        """Remove a leaf directory and all empty intermediate ones
+        """
+        return util.removedirs(self.join(path))
+
     def rmtree(self, path=None, ignore_errors=False, forcibly=False):
         """Remove a directory tree recursively