Fix get_operating_system_and_architecture (#9319)

_get_glibc_version() can after #9005 return either (0, 0) if glibc
string is missing or (-1, -1) if the string can't be parsed. There was
no need to change missing string to (0, 0).

Also, move back indentation to make it easier to understand.

crates/uv-python/python/packaging/_manylinux.py

@@ -173,7 +173,7 @@ def _parse_glibc_version(version_str: str) -> tuple[int, int]:
 def _get_glibc_version() -> tuple[int, int]:
     version_str = _glibc_version_string()
     if version_str is None:
-        return (0, 0)
+        return (-1, -1)
     return _parse_glibc_version(version_str)