fix bug in recording stats for auto-acked tuples when there are no ackers
fix bug in recording stats for auto-acked tuples when there are no ackers

jamesmarva/storm,0x726d77/storm,metamx/incubator-storm,adityasharad/storm,lcp0578/storm,cluo512/storm,Crim/storm,srishtyagrawal/storm,kishorvpatil/incubator-storm,ujfjhz/storm,srdo/storm,pczb/storm,knusbaum/incubator-storm,nathanmarz/storm,chrismoulton/storm,ujfjhz/storm,cluo512/storm,ferrero-zhang/storm,erikdw/storm,srdo/storm,pczb/storm,Aloomaio/incubator-storm,konfer/storm,jamesmarva/storm,lcp0578/storm,kevinconaway/storm,carl34/storm,elancom/storm,ujfjhz/storm,adityasharad/storm,cherryleer/storm,sakanaou/storm,kevpeek/storm,erikdw/storm,raviperi/storm,knusbaum/incubator-storm,cluo512/storm,Crim/storm,carl34/storm,knusbaum/incubator-storm,d2r/storm-marz,kamleshbhatt/storm,gongsm/storm,kevinconaway/storm,kamleshbhatt/storm,hmcl/storm-apache,kevpeek/storm,srdo/storm,3manuek/storm-1,cherryleer/storm,hmcl/storm-apache,cluo512/storm,F30/storm,mesosphere/storm,revans2/incubator-storm,Crim/storm,srishtyagrawal/storm,kishorvpatil/incubator-storm,nathanmarz/storm,konfer/storm,knusbaum/incubator-storm,mesosphere/storm,kishorvpatil/incubator-storm,adityasharad/storm,kishorvpatil/incubator-storm,lcp0578/storm,sakanaou/storm,hilfialkaff/storm,hilfialkaff/storm,kevpeek/storm,chrismoulton/storm,erikdw/storm,kishorvpatil/incubator-storm,kevinconaway/storm,hmcc/storm,rahulkavale/storm,praisondani/storm,nathanmarz/storm,srishtyagrawal/storm,adityasharad/storm,raviperi/storm,allenjin/storm,nathanmarz/storm,kamleshbhatt/storm,srdo/storm,raviperi/storm,d2r/storm-marz,adityasharad/storm,ferrero-zhang/storm,hmcl/storm-apache,kevpeek/storm,hmcc/storm,allenjin/storm,sakanaou/storm,pczb/storm,0x726d77/storm,taoguan/storm-1,hmcc/storm,kamleshbhatt/storm,konfer/storm,konfer/storm,Frostman/storm,chrismoulton/storm,roshannaik/storm,ujfjhz/storm,F30/storm,Frostman/storm,kevinconaway/storm,lcp0578/storm,revans2/storm,hilfialkaff/storm,erikdw/storm,hmcl/storm-apache,d2r/storm-marz,srdo/storm,ujfjhz/storm,revans2/storm,carl34/storm,0x726d77/storm,srishtyagrawal/storm,kishorvpatil/incubator-storm,mesosphere/storm,ferrero-zhang/storm,kamleshbhatt/storm,3manuek/storm-1,F30/storm,Frostman/storm,allenjin/storm,taoguan/storm-1,elancom/storm,sakanaou/storm,erikdw/storm,raviperi/storm,kevinconaway/storm,F30/storm,taoguan/storm-1,hmcc/storm,3manuek/storm-1,3manuek/storm-1,0x726d77/storm,cherryleer/storm,pczb/storm,metamx/incubator-storm,praisondani/storm,hmcc/storm,cluo512/storm,carl34/storm,metamx/incubator-storm,roshannaik/storm,0x726d77/storm,ujfjhz/storm,kamleshbhatt/storm,Crim/storm,metamx/incubator-storm,srdo/storm,revans2/incubator-storm,jamesmarva/storm,allenjin/storm,chrismoulton/storm,kevpeek/storm,Crim/storm,d2r/storm-marz,F30/storm,revans2/incubator-storm,Crim/storm,Crim/storm,revans2/storm,raviperi/storm,praisondani/storm,kevinconaway/storm,adityasharad/storm,kevinconaway/storm,ujfjhz/storm,pczb/storm,nathanmarz/storm,knusbaum/incubator-storm,mesosphere/storm,hilfialkaff/storm,Aloomaio/incubator-storm,Aloomaio/incubator-storm,roshannaik/storm,kamleshbhatt/storm,Aloomaio/incubator-storm,praisondani/storm,hmcl/storm-apache,konfer/storm,mesosphere/storm,gongsm/storm,knusbaum/incubator-storm,erikdw/storm,srishtyagrawal/storm,cherryleer/storm,kevpeek/storm,hmcl/storm-apache,adityasharad/storm,taoguan/storm-1,sakanaou/storm,roshannaik/storm,cherryleer/storm,praisondani/storm,rahulkavale/storm,rahulkavale/storm,F30/storm,kevpeek/storm,Frostman/storm,rahulkavale/storm,elancom/storm,lcp0578/storm,gongsm/storm,hmcl/storm-apache,cluo512/storm,raviperi/storm,raviperi/storm,rahulkavale/storm,srdo/storm,Aloomaio/incubator-storm,metamx/incubator-storm,erikdw/storm,gongsm/storm,revans2/incubator-storm,roshannaik/storm,jamesmarva/storm,carl34/storm,kishorvpatil/incubator-storm,jamesmarva/storm,roshannaik/storm,carl34/storm,0x726d77/storm,srishtyagrawal/storm,taoguan/storm-1,roshannaik/storm,hmcc/storm,pczb/storm,revans2/storm,carl34/storm,revans2/incubator-storm,ferrero-zhang/storm,cluo512/storm,Aloomaio/incubator-storm,hilfialkaff/storm,ferrero-zhang/storm,pczb/storm,0x726d77/storm,knusbaum/incubator-storm,sakanaou/storm,mesosphere/storm,Aloomaio/incubator-storm,d2r/storm-marz,elancom/storm,chrismoulton/storm,elancom/storm,hmcc/storm,F30/storm,gongsm/storm,3manuek/storm-1,srishtyagrawal/storm,revans2/storm,Frostman/storm,allenjin/storm,sakanaou/storm