Turned on executor authentication in the 'DefaultExecutorTests'.
Turned on executor authentication in the 'DefaultExecutorTests'.

Now that executor authentication has been added, this patch
enables authentication for the agent's operator endpoint in
the DefaultExecutorTests. This is only done when build with
SSL, since executor authentication currently has SSL as a
dependency.

Review: https://reviews.apache.org/r/57879/

andschwa/mesos,verizonlabs/mesos,asamerh4/mesos,zmalik/mesos,Gilbert88/mesos,andschwa/mesos,neilconway/mesos,craimbert/mesos,abudnik/mesos,Gilbert88/mesos,chhsia0/mesos,andschwa/mesos,kaysoky/mesos,andschwa/mesos,jpeach/mesos,verizonlabs/mesos,dforsyth/mesos,andschwa/mesos,chhsia0/mesos,chhsia0/mesos,kaysoky/mesos,gsantovena/mesos,neilconway/mesos,asamerh4/mesos,reneploetz/mesos,verizonlabs/mesos,chhsia0/mesos,jpeach/mesos,asamerh4/mesos,neilconway/mesos,verizonlabs/mesos,Gilbert88/mesos,asamerh4/mesos,dforsyth/mesos,reneploetz/mesos,craimbert/mesos,kaysoky/mesos,zmalik/mesos,jpeach/mesos,Gilbert88/mesos,andschwa/mesos,craimbert/mesos,chhsia0/mesos,abudnik/mesos,zmalik/mesos,gsantovena/mesos,abudnik/mesos,gsantovena/mesos,dforsyth/mesos,craimbert/mesos,jpeach/mesos,reneploetz/mesos,craimbert/mesos,zmalik/mesos,jpeach/mesos,gsantovena/mesos,verizonlabs/mesos,gsantovena/mesos,kaysoky/mesos,Gilbert88/mesos,Gilbert88/mesos,abudnik/mesos,asamerh4/mesos,abudnik/mesos,Gilbert88/mesos,zmalik/mesos,reneploetz/mesos,kaysoky/mesos,jpeach/mesos,chhsia0/mesos,reneploetz/mesos,andschwa/mesos,reneploetz/mesos,asamerh4/mesos,neilconway/mesos,kaysoky/mesos,abudnik/mesos,dforsyth/mesos,dforsyth/mesos,neilconway/mesos,asamerh4/mesos,jpeach/mesos,craimbert/mesos,verizonlabs/mesos,neilconway/mesos,dforsyth/mesos,reneploetz/mesos,neilconway/mesos,kaysoky/mesos,chhsia0/mesos,craimbert/mesos,dforsyth/mesos,gsantovena/mesos,verizonlabs/mesos,zmalik/mesos,abudnik/mesos,zmalik/mesos,gsantovena/mesos