Fix host directories naming

[atanasdinov]

Generating configurations from FQDN will unintentionally strip the top-level domain from the names of the host directories (e.g. node1.example instead of node1.example.com):

rdo@tw-aarch64-build:~/nmc-example> tree
.
├── config
│   ├── node1.example.com
│   ├── node2.example.com
│   └── node3.example.com
├── nmc-aarch64
└── out
    ├── host_config.yaml
    ├── node1.example
    │   └── eth0.nmconnection
    ├── node2.example
    │   └── eth0.nmconnection
    └── node3.example
        └── eth0.nmconnection

6 directories, 8 files