Update discovery-ec2.asciidoc
Update discovery-ec2.asciidoc

Changed the recommendation to use Tribe Node to Cross Cluster Search.
kalimatas/elasticsearch,qwerty4030/elasticsearch,wenpos/elasticsearch,masaruh/elasticsearch,ThiagoGarciaAlves/elasticsearch,scorpionvicky/elasticsearch,maddin2016/elasticsearch,robin13/elasticsearch,wangtuo/elasticsearch,rajanm/elasticsearch,GlenRSmith/elasticsearch,fred84/elasticsearch,qwerty4030/elasticsearch,coding0011/elasticsearch,wangtuo/elasticsearch,fred84/elasticsearch,masaruh/elasticsearch,gingerwizard/elasticsearch,HonzaKral/elasticsearch,GlenRSmith/elasticsearch,gingerwizard/elasticsearch,scottsom/elasticsearch,rajanm/elasticsearch,gfyoung/elasticsearch,rajanm/elasticsearch,nknize/elasticsearch,gingerwizard/elasticsearch,robin13/elasticsearch,gfyoung/elasticsearch,maddin2016/elasticsearch,gfyoung/elasticsearch,robin13/elasticsearch,ThiagoGarciaAlves/elasticsearch,fred84/elasticsearch,HonzaKral/elasticsearch,nknize/elasticsearch,scorpionvicky/elasticsearch,scottsom/elasticsearch,kalimatas/elasticsearch,fred84/elasticsearch,gingerwizard/elasticsearch,ThiagoGarciaAlves/elasticsearch,uschindler/elasticsearch,wenpos/elasticsearch,wenpos/elasticsearch,rajanm/elasticsearch,wangtuo/elasticsearch,nknize/elasticsearch,gfyoung/elasticsearch,kalimatas/elasticsearch,wangtuo/elasticsearch,s1monw/elasticsearch,robin13/elasticsearch,qwerty4030/elasticsearch,s1monw/elasticsearch,gingerwizard/elasticsearch,wenpos/elasticsearch,uschindler/elasticsearch,ThiagoGarciaAlves/elasticsearch,qwerty4030/elasticsearch,scottsom/elasticsearch,gfyoung/elasticsearch,coding0011/elasticsearch,wangtuo/elasticsearch,uschindler/elasticsearch,maddin2016/elasticsearch,kalimatas/elasticsearch,s1monw/elasticsearch,qwerty4030/elasticsearch,scorpionvicky/elasticsearch,HonzaKral/elasticsearch,rajanm/elasticsearch,GlenRSmith/elasticsearch,gingerwizard/elasticsearch,scorpionvicky/elasticsearch,kalimatas/elasticsearch,scottsom/elasticsearch,rajanm/elasticsearch,wenpos/elasticsearch,gingerwizard/elasticsearch,coding0011/elasticsearch,robin13/elasticsearch,maddin2016/elasticsearch,scottsom/elasticsearch,ThiagoGarciaAlves/elasticsearch,nknize/elasticsearch,masaruh/elasticsearch,coding0011/elasticsearch,uschindler/elasticsearch,s1monw/elasticsearch,scorpionvicky/elasticsearch,GlenRSmith/elasticsearch,uschindler/elasticsearch,GlenRSmith/elasticsearch,masaruh/elasticsearch,HonzaKral/elasticsearch,masaruh/elasticsearch,s1monw/elasticsearch,fred84/elasticsearch,nknize/elasticsearch,ThiagoGarciaAlves/elasticsearch,maddin2016/elasticsearch,coding0011/elasticsearch