Updated endpoint help generator script to work inside Docker.
Updated endpoint help generator script to work inside Docker.

Changed agent flags to make this script work inside Docker container.
This is needed because this script will be run as part of website
publishing process which runs on ASF CI inside Docker.

Review: https://reviews.apache.org/r/60438

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