fix L0 time array overflow due to null L0 threshold from OCDB EMCAL-39
fix L0 time array overflow due to null L0 threshold from OCDB EMCAL-39

coppedis/AliRoot,sebaleh/AliRoot,alisw/AliRoot,ALICEHLT/AliRoot,shahor02/AliRoot,miranov25/AliRoot,miranov25/AliRoot,ALICEHLT/AliRoot,miranov25/AliRoot,ALICEHLT/AliRoot,coppedis/AliRoot,coppedis/AliRoot,alisw/AliRoot,coppedis/AliRoot,miranov25/AliRoot,shahor02/AliRoot,ALICEHLT/AliRoot,alisw/AliRoot,sebaleh/AliRoot,coppedis/AliRoot,alisw/AliRoot,ALICEHLT/AliRoot,sebaleh/AliRoot,ALICEHLT/AliRoot,alisw/AliRoot,miranov25/AliRoot,shahor02/AliRoot,sebaleh/AliRoot,ALICEHLT/AliRoot,miranov25/AliRoot,shahor02/AliRoot,coppedis/AliRoot,shahor02/AliRoot,shahor02/AliRoot,coppedis/AliRoot,sebaleh/AliRoot,alisw/AliRoot,sebaleh/AliRoot,shahor02/AliRoot,coppedis/AliRoot,alisw/AliRoot,alisw/AliRoot,miranov25/AliRoot,miranov25/AliRoot,sebaleh/AliRoot