packaging: Just permit anything if PAM is enabled

packaging: Just permit anything if PAM is enabled

With a current pam_rootok.so, it works only with `root` account. If the user
is under `frrvty`, `frr` group, it gets the error:

```
% groups | grep -o -E "frrvty|frr"
frrvty
frr

% vtysh -c 'end'
vtysh_pam: Failed in account validation: Permission denied(6)
```

Checking the logs:

```
vtysh[23930]: pam_rootok(frr:account): root check failed
```

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>