Updated the docker executor to use health checks via the library.
Updated the docker executor to use health checks via the library.

We updated the command executor to use health checks via library in
https://reviews.apache.org/r/49389/. This patch updates the docker
executor for consistency.

Review: https://reviews.apache.org/r/49555/

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