Relax a KASSERT to allow the timer to be stopped when it is about to be running off.
Relax a KASSERT to allow the timer to be stopped when it is about
to be running off.

Thanks to Timo Voelker for finding and reporting the bug and
suggesting a fix.

sctplab/usrsctp,sctplab/usrsctp,weinrank/usrsctp,CoolmanCZ/usrsctp,CoolmanCZ/usrsctp,sctplab/usrsctp,CoolmanCZ/usrsctp,weinrank/usrsctp,CoolmanCZ/usrsctp,weinrank/usrsctp