Docker environment gets passed on docker run command.
Docker environment gets passed on docker run command.

Removes the use of `--env_file` as that does not support newlines
in environment variable values. Also avoids leaking of possibly
sensitive environment variables to the log.

Review: https://reviews.apache.org/r/57846/

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