Fix running docker executor tests.
Fix running docker executor tests.

Review: https://reviews.apache.org/r/36214

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