do not ignore user configured JAVA_HOME
do not ignore user configured JAVA_HOME

Patch by eevans; reviewed by Michael Shuler for CASSANDRA-6131

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