Automatic merge from submit-queue (batch tested with PRs 43304, 41427, 43490, 44352)
Update etcd-client godep to 3.1.5
This transitively level sets the godeps to yank in the 3.1.5 client.
Currently WIP, b/c it required some regen and I had some weird local permissions issue.
xref: #41143
/cc @xiang90 @mml