Added warning to `apply-reviews.py` for submitted patches.
Added warning to `apply-reviews.py` for submitted patches.

This commit emits a warning when a chain skips submitted patches so
that the user is aware they were ignored.

Review: https://reviews.apache.org/r/65795/

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