Added filtering for orphaned tasks in /state endpoint.
Added filtering for orphaned tasks in /state endpoint.

Review: https://reviews.apache.org/r/49609/

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