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