Fix deallocation in queuebuf.c, case where QUEUEBUF_STATS is set
Fix deallocation in queuebuf.c, case where QUEUEBUF_STATS is set

MohamedSeliem/contiki,arurke/contiki,arurke/contiki,MohamedSeliem/contiki,arurke/contiki,MohamedSeliem/contiki,bluerover/6lbr,bluerover/6lbr,bluerover/6lbr,bluerover/6lbr,arurke/contiki,MohamedSeliem/contiki,bluerover/6lbr,bluerover/6lbr,arurke/contiki,MohamedSeliem/contiki,MohamedSeliem/contiki,arurke/contiki,bluerover/6lbr,MohamedSeliem/contiki,arurke/contiki