net.get_interfaces() raises FileNotFoundError when network interface is renamed during enumeration

device_driver() & get_interfaces() may need some work to be resilient if an interface is being renamed while enumerating devices:

```
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/cloudinit/sources/DataSourceAzure.py", line 860, in _get_data
crawled_data = util.log_time(
File "/usr/lib/python3/dist-packages/cloudinit/util.py", line 2808, in log_time
ret = func(*args, **kwargs)
File "/usr/lib/python3/dist-packages/cloudinit/sources/helpers/azure.py", line 59, in impl
return func(*args, **kwargs)
File "/usr/lib/python3/dist-packages/cloudinit/sources/DataSourceAzure.py", line 639, in crawl_metadata
self._setup_ephemeral_networking(timeout_minutes=timeout_minutes)
File "/usr/lib/python3/dist-packages/cloudinit/sources/helpers/azure.py", line 59, in impl
return func(*args, **kwargs)
File "/usr/lib/python3/dist-packages/cloudinit/sources/DataSourceAzure.py", line 424, in _setup_ephemeral_networking
% (iface, net.get_interfaces()),
File "/usr/lib/python3/dist-packages/cloudinit/net/__init__.py", line 1079, in get_interfaces
driver = device_driver(name)
File "/usr/lib/python3/dist-packages/cloudinit/net/__init__.py", line 364, in device_driver
driver = os.path.basename(os.readlink(driver_path))
FileNotFoundError: [Errno 2] No such file or directory: '/sys/class/net/ib0/device/driver'
```

Around the same time we can see the interfaces are being renamed:

```
[ 36.915981] mlx5_core 0101:00:00.0 ibP257s165943: renamed from ib0
[ 36.953812] mlx5_core 0102:00:00.0 ibP258s165981: renamed from ib0
[ 37.057541] mlx5_core 0103:00:00.0 ibP259s166052: renamed from ib0
[ 37.104314] mlx5_core 0104:00:00.0 ibP260s166131: renamed from ib0
[ 37.157170] mlx5_core 0105:00:00.0 ibP261s166145: renamed from ib0
[ 37.208995] mlx5_core 0106:00:00.0 ibP262s166254: renamed from ib0
[ 37.240758] mlx5_core 0107:00:00.0 ibP263s166326: renamed from ib0
[ 37.276640] mlx5_core 0108:00:00.0 ibP264s166393: renamed from ib0
```