Updated killTask to only send TASK_LOST when a strict registry is in use.
Updated killTask to only send TASK_LOST when a strict registry is in use.

Review: https://reviews.apache.org/r/20140

neilconway/mesos,yuquanshan/customizedMesos,asamerh4/mesos,reneploetz/mesos,andschwa/mesos,asamerh4/mesos,verizonlabs/mesos,yuquanshan/customizedMesos,yuquanshan/customizedMesos,asamerh4/mesos,kaysoky/mesos,zmalik/mesos,dforsyth/mesos,gsantovena/mesos,gsantovena/mesos,craimbert/mesos,Gilbert88/mesos,reneploetz/mesos,zmalik/mesos,jpeach/mesos,verizonlabs/mesos,Gilbert88/mesos,gsantovena/mesos,chhsia0/mesos,gsantovena/mesos,andschwa/mesos,asamerh4/mesos,reneploetz/mesos,gsantovena/mesos,andschwa/mesos,Gilbert88/mesos,Gilbert88/mesos,Aman-Jain-14/customizedMesos,craimbert/mesos,kaysoky/mesos,verizonlabs/mesos,verizonlabs/mesos,abudnik/mesos,jpeach/mesos,jpeach/mesos,yuquanshan/customizedMesos,reneploetz/mesos,Gilbert88/mesos,reneploetz/mesos,Aman-Jain-14/customizedMesos,chhsia0/mesos,verizonlabs/mesos,verizonlabs/mesos,zmalik/mesos,dforsyth/mesos,yuquanshan/customizedMesos,jpeach/mesos,abudnik/mesos,craimbert/mesos,Aman-Jain-14/customizedMesos,craimbert/mesos,jpeach/mesos,chhsia0/mesos,reneploetz/mesos,craimbert/mesos,abudnik/mesos,kaysoky/mesos,dforsyth/mesos,zmalik/mesos,chhsia0/mesos,Aman-Jain-14/customizedMesos,chhsia0/mesos,Aman-Jain-14/customizedMesos,abudnik/mesos,Aman-Jain-14/customizedMesos,kaysoky/mesos,zmalik/mesos,neilconway/mesos,kaysoky/mesos,zmalik/mesos,neilconway/mesos,yuquanshan/customizedMesos,gsantovena/mesos,neilconway/mesos,Gilbert88/mesos,gsantovena/mesos,Aman-Jain-14/customizedMesos,andschwa/mesos,zmalik/mesos,reneploetz/mesos,chhsia0/mesos,Gilbert88/mesos,yuquanshan/customizedMesos,neilconway/mesos,craimbert/mesos,verizonlabs/mesos,dforsyth/mesos,andschwa/mesos,dforsyth/mesos,chhsia0/mesos,andschwa/mesos,abudnik/mesos,andschwa/mesos,jpeach/mesos,jpeach/mesos,kaysoky/mesos,dforsyth/mesos,neilconway/mesos,abudnik/mesos,craimbert/mesos,asamerh4/mesos,abudnik/mesos,kaysoky/mesos,asamerh4/mesos,dforsyth/mesos,neilconway/mesos,asamerh4/mesos