cqlsh: check for non-empty history file before loading Patch by Brian O'Neill, reviewed by brandonwilliams for CASSANDRA-4669
cqlsh: check for non-empty history file before loading
Patch by Brian O'Neill, reviewed by brandonwilliams for CASSANDRA-4669

mheffner/cassandra-1,Instagram/cassandra,scylladb/scylla-tools-java,rmarchei/cassandra,rmarchei/cassandra,scylladb/scylla-tools-java,sayanh/ViewMaintenanceCassandra,jkni/cassandra,HidemotoNakada/cassandra-udf,jkni/cassandra,belliottsmith/cassandra,guard163/cassandra,sedulam/CASSANDRA-12201,yhnishi/cassandra,DavidHerzogTU-Berlin/cassandra,sedulam/CASSANDRA-12201,pcn/cassandra-1,szhou1234/cassandra,strapdata/cassandra,pcmanus/cassandra,iburmistrov/Cassandra,jbellis/cassandra,bcoverston/cassandra,helena/cassandra,clohfink/cassandra,bcoverston/cassandra,krummas/cassandra,wreda/cassandra,mkjellman/cassandra,scylladb/scylla-tools-java,guard163/cassandra,thobbs/cassandra,jrwest/cassandra,pallavi510/cassandra,sluk3r/cassandra,mshuler/cassandra,bmel/cassandra,xiongzheng/Cassandra-Research,dongjiaqiang/cassandra,joesiewert/cassandra,pauloricardomg/cassandra,Bj0rnen/cassandra,project-zerus/cassandra,kangkot/stratio-cassandra,pcmanus/cassandra,mambocab/cassandra,vramaswamy456/cassandra,project-zerus/cassandra,chbatey/cassandra-1,mshuler/cassandra,darach/cassandra,krummas/cassandra,GabrielNicolasAvellaneda/cassandra,mkjellman/cassandra,jeffjirsa/cassandra,AtwooTM/cassandra,sayanh/ViewMaintenanceSupport,matthewtt/cassandra_read,whitepages/cassandra,snazy/cassandra,nitsanw/cassandra,stef1927/cassandra,Instagram/cassandra,ibmsoe/cassandra,Stratio/cassandra,fengshao0907/cassandra-1,mike-tr-adamson/cassandra,jsanda/cassandra,xiongzheng/Cassandra-Research,tongjixianing/projects,adejanovski/cassandra,spodkowinski/cassandra,kgreav/cassandra,josh-mckenzie/cassandra,josh-mckenzie/cassandra,GabrielNicolasAvellaneda/cassandra,taigetco/cassandra_read,caidongyun/cassandra,Jollyplum/cassandra,nitsanw/cassandra,bdeggleston/cassandra,nakomis/cassandra,bdeggleston/cassandra,vaibhi9/cassandra,Stratio/stratio-cassandra,Jollyplum/cassandra,RyanMagnusson/cassandra,qinjin/mdtc-cassandra,fengshao0907/Cassandra-Research,nvoron23/cassandra,jeromatron/cassandra,aweisberg/cassandra,pcn/cassandra-1,mgmuscari/cassandra-cdh4,vaibhi9/cassandra,DikangGu/cassandra,caidongyun/cassandra,yonglehou/cassandra,a-buck/cassandra,ifesdjeen/cassandra,emolsson/cassandra,emolsson/cassandra,EnigmaCurry/cassandra,mashuai/Cassandra-Research,JeremiahDJordan/cassandra,blambov/cassandra,carlyeks/cassandra,dkua/cassandra,aureagle/cassandra,michaelsembwever/cassandra,caidongyun/cassandra,strapdata/cassandra,ptuckey/cassandra,michaelsembwever/cassandra,rogerchina/cassandra,hhorii/cassandra,carlyeks/cassandra,pofallon/cassandra,pkdevbox/cassandra,hengxin/cassandra,driftx/cassandra,iamaleksey/cassandra,wreda/cassandra,a-buck/cassandra,yangzhe1991/cassandra,weipinghe/cassandra,ptnapoleon/cassandra,knifewine/cassandra,gdusbabek/cassandra,sayanh/ViewMaintenanceCassandra,likaiwalkman/cassandra,DikangGu/cassandra,iamaleksey/cassandra,swps/cassandra,blambov/cassandra,sbtourist/cassandra,guard163/cassandra,cooldoger/cassandra,darach/cassandra,ben-manes/cassandra,apache/cassandra,krummas/cassandra,LatencyUtils/cassandra-stress2,chaordic/cassandra,pallavi510/cassandra,aboudreault/cassandra,bpupadhyaya/cassandra,fengshao0907/Cassandra-Research,yanbit/cassandra,yukim/cassandra,asias/cassandra,snazy/cassandra,clohfink/cassandra,vaibhi9/cassandra,bmel/cassandra,regispl/cassandra,tongjixianing/projects,whitepages/cassandra,shawnkumar/cstargraph,a-buck/cassandra,thelastpickle/cassandra,pcn/cassandra-1,ptnapoleon/cassandra,beobal/cassandra,tjake/cassandra,DICL/cassandra,Jollyplum/cassandra,christian-esken/cassandra,Stratio/cassandra,scylladb/scylla-tools-java,WorksApplications/cassandra,tongjixianing/projects,ifesdjeen/cassandra,iburmistrov/Cassandra,ollie314/cassandra,jasonwee/cassandra,stef1927/cassandra,sayanh/ViewMaintenanceCassandra,HidemotoNakada/cassandra-udf,jsanda/cassandra,LatencyUtils/cassandra-stress2,fengshao0907/Cassandra-Research,taigetco/cassandra_read,leomrocha/cassandra,scaledata/cassandra,adelapena/cassandra,sedulam/CASSANDRA-12201,hhorii/cassandra,beobal/cassandra,pauloricardomg/cassandra,cooldoger/cassandra,sharvanath/cassandra,christian-esken/cassandra,leomrocha/cassandra,chaordic/cassandra,christian-esken/cassandra,aarushi12002/cassandra,weideng1/cassandra,juiceblender/cassandra,RyanMagnusson/cassandra,adejanovski/cassandra,heiko-braun/cassandra,vramaswamy456/cassandra,bmel/cassandra,tommystendahl/cassandra,MasahikoSawada/cassandra,boneill42/cassandra,boneill42/cassandra,apache/cassandra,weideng1/cassandra,DavidHerzogTU-Berlin/cassandraToRun,knifewine/cassandra,yhnishi/cassandra,pthomaid/cassandra,DavidHerzogTU-Berlin/cassandraToRun,chbatey/cassandra-1,aarushi12002/cassandra,rogerchina/cassandra,rmarchei/cassandra,newrelic-forks/cassandra,iamaleksey/cassandra,sriki77/cassandra,Instagram/cassandra,lalithsuresh/cassandra-c3,mambocab/cassandra,nlalevee/cassandra,guanxi55nba/db-improvement,aboudreault/cassandra,lalithsuresh/cassandra-c3,swps/cassandra,HidemotoNakada/cassandra-udf,Stratio/stratio-cassandra,aweisberg/cassandra,jasonwee/cassandra,lalithsuresh/cassandra-c3,Imran-C/cassandra,heiko-braun/cassandra,belliottsmith/cassandra,instaclustr/cassandra,newrelic-forks/cassandra,joesiewert/cassandra,RyanMagnusson/cassandra,nvoron23/cassandra,belliottsmith/cassandra,blambov/cassandra,whitepages/cassandra,DavidHerzogTU-Berlin/cassandraToRun,sluk3r/cassandra,pofallon/cassandra,adejanovski/cassandra,matthewtt/cassandra_read,beobal/cassandra,DICL/cassandra,shawnkumar/cstargraph,beobal/cassandra,adelapena/cassandra,rackerlabs/cloudmetrics-cassandra,nutbunnies/cassandra,codefollower/Cassandra-Research,mashuai/Cassandra-Research,mashuai/Cassandra-Research,mt0803/cassandra,driftx/cassandra,thelastpickle/cassandra,juiceblender/cassandra,tjake/cassandra,josh-mckenzie/cassandra,WorksApplications/cassandra,szhou1234/cassandra,yangzhe1991/cassandra,michaelmior/cassandra,jasonstack/cassandra,instaclustr/cassandra,nutbunnies/cassandra,nutbunnies/cassandra,blerer/cassandra,Imran-C/cassandra,bcoverston/cassandra,Stratio/stratio-cassandra,macintoshio/cassandra,michaelsembwever/cassandra,tjake/cassandra,nlalevee/cassandra,tommystendahl/cassandra,phact/cassandra,DICL/cassandra,modempachev4/kassandra,GabrielNicolasAvellaneda/cassandra,tommystendahl/cassandra,joesiewert/cassandra,miguel0afd/cassandra-cqlMod,mheffner/cassandra-1,hengxin/cassandra,thelastpickle/cassandra,hhorii/cassandra,regispl/cassandra,guanxi55nba/key-value-store,leomrocha/cassandra,sriki77/cassandra,spodkowinski/cassandra,Bj0rnen/cassandra,vramaswamy456/cassandra,mkjellman/cassandra,jeromatron/cassandra,pkdevbox/cassandra,ptnapoleon/cassandra,jkni/cassandra,ptuckey/cassandra,rogerchina/cassandra,WorksApplications/cassandra,sbtourist/cassandra,josh-mckenzie/cassandra,MasahikoSawada/cassandra,guanxi55nba/db-improvement,sharvanath/cassandra,jeffjirsa/cassandra,ollie314/cassandra,Stratio/stratio-cassandra,macintoshio/cassandra,qinjin/mdtc-cassandra,jbellis/cassandra,mgmuscari/cassandra-cdh4,yukim/cassandra,blerer/cassandra,yonglehou/cassandra,snazy/cassandra,bpupadhyaya/cassandra,thobbs/cassandra,xiongzheng/Cassandra-Research,gdusbabek/cassandra,rdio/cassandra,qinjin/mdtc-cassandra,tommystendahl/cassandra,jsanda/cassandra,Stratio/stratio-cassandra,AtwooTM/cassandra,bpupadhyaya/cassandra,dkua/cassandra,pcmanus/cassandra,AtwooTM/cassandra,aarushi12002/cassandra,pauloricardomg/cassandra,tjake/cassandra,kgreav/cassandra,nakomis/cassandra,newrelic-forks/cassandra,Bj0rnen/cassandra,Imran-C/cassandra,rdio/cassandra,likaiwalkman/cassandra,gdusbabek/cassandra,dongjiaqiang/cassandra,fengshao0907/cassandra-1,phact/cassandra,bdeggleston/cassandra,adelapena/cassandra,jeffjirsa/cassandra,helena/cassandra,LatencyUtils/cassandra-stress2,Jaumo/cassandra,jeromatron/cassandra,jasonstack/cassandra,WorksApplications/cassandra,cooldoger/cassandra,macintoshio/cassandra,exoscale/cassandra,aweisberg/cassandra,blerer/cassandra,Stratio/cassandra,pauloricardomg/cassandra,weideng1/cassandra,mike-tr-adamson/cassandra,kangkot/stratio-cassandra,modempachev4/kassandra,michaelmior/cassandra,shawnkumar/cstargraph,spodkowinski/cassandra,wreda/cassandra,sayanh/ViewMaintenanceSupport,Jaumo/cassandra,instaclustr/cassandra,szhou1234/cassandra,JeremiahDJordan/cassandra,DikangGu/cassandra,pofallon/cassandra,clohfink/cassandra,likaiwalkman/cassandra,blambov/cassandra,ifesdjeen/cassandra,driftx/cassandra,boneill42/cassandra,weipinghe/cassandra,phact/cassandra,mshuler/cassandra,kangkot/stratio-cassandra,helena/cassandra,codefollower/Cassandra-Research,scaledata/cassandra,michaelmior/cassandra,MasahikoSawada/cassandra,emolsson/cassandra,chaordic/cassandra,kangkot/stratio-cassandra,driftx/cassandra,codefollower/Cassandra-Research,nitsanw/cassandra,yanbit/cassandra,ollie314/cassandra,juiceblender/cassandra,jeffjirsa/cassandra,yukim/cassandra,JeremiahDJordan/cassandra,DavidHerzogTU-Berlin/cassandra,sriki77/cassandra,ibmsoe/cassandra,exoscale/cassandra,mt0803/cassandra,asias/cassandra,jasobrown/cassandra,strapdata/cassandra,guanxi55nba/key-value-store,miguel0afd/cassandra-cqlMod,krummas/cassandra,mambocab/cassandra,jbellis/cassandra,yangzhe1991/cassandra,yhnishi/cassandra,Jaumo/cassandra,hengxin/cassandra,spodkowinski/cassandra,chbatey/cassandra-1,darach/cassandra,ben-manes/cassandra,kangkot/stratio-cassandra,stef1927/cassandra,swps/cassandra,bdeggleston/cassandra,scaledata/cassandra,dongjiaqiang/cassandra,snazy/cassandra,jasobrown/cassandra,nlalevee/cassandra,sivikt/cassandra,pthomaid/cassandra,pthomaid/cassandra,ifesdjeen/cassandra,pallavi510/cassandra,belliottsmith/cassandra,nakomis/cassandra,mheffner/cassandra-1,matthewtt/cassandra_read,kgreav/cassandra,jasobrown/cassandra,bcoverston/apache-hosted-cassandra,sluk3r/cassandra,nvoron23/cassandra,ejankan/cassandra,bcoverston/cassandra,bcoverston/apache-hosted-cassandra,DavidHerzogTU-Berlin/cassandra,ejankan/cassandra,bcoverston/apache-hosted-cassandra,mt0803/cassandra,sivikt/cassandra,mgmuscari/cassandra-cdh4,mshuler/cassandra,EnigmaCurry/cassandra,mkjellman/cassandra,guanxi55nba/db-improvement,dprguiuc/Cassandra-Wasef,iburmistrov/Cassandra,instaclustr/cassandra,ibmsoe/cassandra,thelastpickle/cassandra,yukim/cassandra,dkua/cassandra,aweisberg/cassandra,kgreav/cassandra,szhou1234/cassandra,regispl/cassandra,ptuckey/cassandra,dprguiuc/Cassandra-Wasef,ejankan/cassandra,EnigmaCurry/cassandra,iamaleksey/cassandra,stef1927/cassandra,sharvanath/cassandra,carlyeks/cassandra,jrwest/cassandra,blerer/cassandra,jrwest/cassandra,modempachev4/kassandra,clohfink/cassandra,project-zerus/cassandra,jasonstack/cassandra,rdio/cassandra,fengshao0907/cassandra-1,weipinghe/cassandra,pkdevbox/cassandra,aboudreault/cassandra,asias/cassandra,jasonwee/cassandra,jasobrown/cassandra,aureagle/cassandra,michaelsembwever/cassandra,adelapena/cassandra,rackerlabs/cloudmetrics-cassandra,yanbit/cassandra,sbtourist/cassandra,mike-tr-adamson/cassandra,jrwest/cassandra,cooldoger/cassandra,guanxi55nba/key-value-store,exoscale/cassandra,heiko-braun/cassandra,juiceblender/cassandra,apache/cassandra,taigetco/cassandra_read,thobbs/cassandra,aureagle/cassandra,dprguiuc/Cassandra-Wasef,miguel0afd/cassandra-cqlMod,sivikt/cassandra,ben-manes/cassandra,apache/cassandra,rackerlabs/cloudmetrics-cassandra,Instagram/cassandra,knifewine/cassandra,strapdata/cassandra,yonglehou/cassandra,mike-tr-adamson/cassandra