The problem with org-babel-post-tangle-hook is that user is always asked
yes-or-no-p for file reversion. Calling auto revert (as Rainer tried)
will not help.

The problem is in find-file-noselect in org-babel-find-file-noselect-refresh.

The following patch fixes it by silencing find-file-noselect. Besides
reversion question, there are a couple of other warning/questions that
are silenced, but given that org-babel-find-file-noselect-refresh is
used only for reverting tangled files, this is probably not an issue.

  Vitalie