Fixed build dependency for `protobuf_tests.proto`.
Fixed build dependency for `protobuf_tests.proto`.

The protobuf hpp and cpp files for `protobuf_tests.proto` should be
built after `BUNDLED_DEPS`, not within it.

Review: https://reviews.apache.org/r/62777/

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