Fixed `mesos-tcp-connect` to use `net::socket`.
Fixed `mesos-tcp-connect` to use `net::socket`.

Use the stout wrapper instead of `::socket` so we have built-in error
checking (and don't have to worry about types).

Review: https://reviews.apache.org/r/66836

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