[SIGAR-85] Fix possible integer overflow in sigar_file_system_usage
[SIGAR-85] Fix possible integer overflow in sigar_file_system_usage

hyperic/sigar,racker/sigar,ruleless/sigar,monicasarbu/sigar,abhinavmishra14/sigar,kaustavha/sigar,abhinavmishra14/sigar,racker/sigar,OlegYch/sigar,abhinavmishra14/sigar,monicasarbu/sigar,ChunPIG/sigar,lsjeng/sigar,formicary/sigar,ChunPIG/sigar,ChunPIG/sigar,scouter-project/sigar,monicasarbu/sigar,scouter-project/sigar,boundary/sigar,OlegYch/sigar,abhinavmishra14/sigar,abhinavmishra14/sigar,monicasarbu/sigar,ChunPIG/sigar,ChunPIG/sigar,boundary/sigar,OlegYch/sigar,cit-lab/sigar,monicasarbu/sigar,racker/sigar,ruleless/sigar,OlegYch/sigar,kaustavha/sigar,formicary/sigar,scouter-project/sigar,scouter-project/sigar,cit-lab/sigar,ruleless/sigar,monicasarbu/sigar,racker/sigar,hyperic/sigar,lsjeng/sigar,cit-lab/sigar,boundary/sigar,hyperic/sigar,boundary/sigar,racker/sigar,lsjeng/sigar,OlegYch/sigar,abhinavmishra14/sigar,lsjeng/sigar,kaustavha/sigar,formicary/sigar,cit-lab/sigar,kaustavha/sigar,formicary/sigar,ruleless/sigar,scouter-project/sigar,lsjeng/sigar,lsjeng/sigar,cit-lab/sigar,cit-lab/sigar,kaustavha/sigar,boundary/sigar,hyperic/sigar,racker/sigar,formicary/sigar,ChunPIG/sigar,boundary/sigar,racker/sigar,racker/sigar,hyperic/sigar,hyperic/sigar,monicasarbu/sigar,formicary/sigar,scouter-project/sigar,boundary/sigar,OlegYch/sigar,OlegYch/sigar,boundary/sigar,racker/sigar,ruleless/sigar,cit-lab/sigar,cit-lab/sigar,cit-lab/sigar,ruleless/sigar,hyperic/sigar,lsjeng/sigar,formicary/sigar,kaustavha/sigar,ruleless/sigar,ChunPIG/sigar,ChunPIG/sigar,kaustavha/sigar,couchbase/sigar,monicasarbu/sigar,couchbase/sigar,hyperic/sigar,hyperic/sigar,abhinavmishra14/sigar,cit-lab/sigar,kaustavha/sigar,kaustavha/sigar,OlegYch/sigar,monicasarbu/sigar,formicary/sigar,lsjeng/sigar,lsjeng/sigar,scouter-project/sigar,hyperic/sigar,scouter-project/sigar,OlegYch/sigar,boundary/sigar,ruleless/sigar,abhinavmishra14/sigar,boundary/sigar,ruleless/sigar,cit-lab/sigar,abhinavmishra14/sigar,formicary/sigar,abhinavmishra14/sigar,formicary/sigar,OlegYch/sigar,kaustavha/sigar,ruleless/sigar,scouter-project/sigar,ChunPIG/sigar,monicasarbu/sigar,ChunPIG/sigar,racker/sigar,scouter-project/sigar,lsjeng/sigar,monicasarbu/sigar,kaustavha/sigar,scouter-project/sigar,abhinavmishra14/sigar,hyperic/sigar