Fix a bug reported by Daniel Mentz: DATA chunks get stuck when using SCTP-AUTH and the PMTU decreases.
Fix a bug reported by Daniel Mentz: DATA chunks get stuck when using
SCTP-AUTH and the PMTU decreases.

ossy-szeged/sctp-refimpl,ossy-szeged/sctp-refimpl,ossy-szeged/sctp-refimpl,ossy-szeged/sctp-refimpl,ossy-szeged/sctp-refimpl,ossy-szeged/sctp-refimpl,ossy-szeged/sctp-refimpl,ossy-szeged/sctp-refimpl,ossy-szeged/sctp-refimpl