etcd: Fix firstSession error handling
etcd: Fix firstSession error handling

The commit bf8e4327448 ("etcd: Ensure that firstSession is closed")
incorrectly assumed that only a single reader exists for firstSession. This is
not the case and the error returned via the channel will only be read by one of
the readers, the other readers will assume success and continue in their code
logic even though the etcd client is being shut down.

Fixes: bf8e4327448
Signed-off-by: Thomas Graf <5f50a84c1fa3bcff146405017f36aec1a10a9e38@cilium.io>
Signed-off-by: Joe Stringer <16a9a54ddf4259952e3c118c763138e83693d7fd@cilium.io>

tklauser/cilium,tklauser/cilium,cilium/cilium,michi-covalent/cilium,cilium-team/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,tgraf/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,tklauser/cilium,michi-covalent/cilium,tgraf/cilium,cilium/cilium,tgraf/cilium,cilium-team/cilium,tgraf/cilium,tgraf/cilium,michi-covalent/cilium,tklauser/cilium,michi-covalent/cilium