Automatic merge from submit-queue

kubectl: add less verbose version

The kubectl version output is very complex and makes it hard for users
and vendors to give actionable information. For example during the
recent Kubernetes 1.4.3 TLS security scramble I had to write a one-liner
for users to get out the version number to give to figure out if they
are vulnerable:

```
$ kubectl version | grep -i Server | sed  -n 's%.*GitVersion:"\([^"]*\).*%\1%p'
```

Instead this patch outputs simply output by default

```
./kubectl version
Client Version: v1.4.3
Server Version: v1.4.3
```

Adding the `--verbose` flag will output the old format.