Fixed issue in the webui where task counts did not update.
Fixed issue in the webui where task counts did not update.

Review: https://reviews.apache.org/r/38056

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