Fixed a bug in 'ComposingContainerizerProcess::wait()'.
Fixed a bug in 'ComposingContainerizerProcess::wait()'.

Fixed a bug in the Composing Containerizer that would make it always
immediately return 'None' when trying to wait on a nested container
that had already been terminated and whose exit status was checkpointed.

Review: https://reviews.apache.org/r/59537/

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