Tests for subscribe/failover functionality for HTTP based framework.
Tests for subscribe/failover functionality for HTTP based framework.

This implements the tests for HTTP framework subscribe/failover/upgrade
from a PID based framework. The test are parameterized on content type
and hence test both JSON/Protobuf responses.

Review: https://reviews.apache.org/r/37082

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