./install.sh host requires sudo password (even if it is disabled)

I have disabled sudo password confirmation for my user; at the same time cluster provisioning command requires it:

```
idv@intel-nuc:~/k8s-devbox⟫ ./install.sh host 
SUDO password: 
```

Please, fix this behaviour.

PS. Running the same command under `root` user requires `sudo` password as well:

```
root@intel-nuc:~/k8s-devbox# ./install.sh host
SUDO password: 
```
