Added labels to docker v1 spec config.
Added labels to docker v1 spec config.

Review: https://reviews.apache.org/r/47198/

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