remove overwriting the named return value (err) by a defer in istioctl kube-inject (#2334)
remove overwriting the named return value (err) by a defer in istioctl kube-inject (#2334)

Automatic merge from submit-queue.

remove overwriting the named return value (err) by a defer in istioctl kube-inject

Also unified defers and variable names of input and output files.

It is a bug, solves removed overwriting a named return value (err) by a defer
https://github.com/istio/issues/issues/133
frankbu/istio,smawson/istio,frankbu/istio,istio/istio,geeknoid/istio,istio/istio,frankbu/istio,geeknoid/istio,istio/istio,smawson/istio,smawson/istio,frankbu/istio,geeknoid/istio,geeknoid/istio,geeknoid/istio,frankbu/istio,frankbu/istio,smawson/istio,istio/istio,smawson/istio,geeknoid/istio,smawson/istio,istio/istio