fix a memleak
fix a memleak

cr-marcstevens/fplll,cr-marcstevens/fplll,dstehle/fplll,fplll/fplll,fplll/fplll,fplll/fplll,dstehle/fplll,fplll/fplll,cr-marcstevens/fplll,cr-marcstevens/fplll,fplll/fplll,dstehle/fplll