python/sepolicy: Fix get_os_version except clause

This adds more exceptions to be handled by the except clause in
`get_os_version()`:

* If the `distro` package is not installed, then `import distro` raises
  a `ModuleNotFoundError` exception.

* The distro documentation[1] lists `OSError` and `UnicodeError` as
  exceptions that can be raised.

* Older versions of distro (<= 1.6.0) may also raise
  `subprocessCalledProcessError`[2].

[1]: https://github.com/python-distro/distro/blob/v1.8.0/src/distro/distro.py#L749-L753
[2]: https://github.com/python-distro/distro/blob/v1.6.0/distro.py#L726-L728

Signed-off-by: Jeffery To <[email protected]>
Acked-by: Petr Lautrbach <[email protected]>

Author: jefferyto

python/sepolicy/sepolicy/__init__.py

@@ -1240,11 +1240,12 @@ def boolean_desc(boolean):
 
 
 def get_os_version():
+    import subprocess
     system_release = ""
     try:
         import distro
         system_release = distro.name(pretty=True)
-    except IOError:
+    except (ModuleNotFoundError, OSError, IOError, UnicodeError, subprocess.CalledProcessError):
         system_release = "Misc"
 
     return system_release