[popen] concatenate instead of splat for popen shell
[popen] concatenate instead of splat for popen shell

upfluence/sensu,yonglehou/sensu,rbramwell/sensu,Tapjoy/sensu-mirror,pauloconnor/sensu,sensu/sensu,zuazo-forks/sensu,javrasya/sensu,withnale/sensu,roobert/sensu,quodlibetor/sensu,npe9/sensu,somic/sensu,portertech/sensu,keymone/sensu,crewton/sensu,solarkennedy/sensu,miyakawataku/sensu,cread/sensu,m4ce/sensu,bf4/sensu