I can confirm that the proposed package fixes the bug for me.
I did not have readahead-fedora package, but ureadahead. However, I had fedora-readahead with 14.04. It is possible that some files were not removed during upgrade to 15.04. apt-get remove ureadahead; apt-get purge readahead-fedora fixed this for me (in addition to using the proposed setserial). Now nfsd starts.
I can confirm that the proposed package fixes the bug for me.
I did not have readahead-fedora package, but ureadahead. However, I had fedora-readahead with 14.04. It is possible that some files were not removed during upgrade to 15.04. apt-get remove ureadahead; apt-get purge readahead-fedora fixed this for me (in addition to using the proposed setserial). Now nfsd starts.