python/sepolicy: Use xml.etree.ElementTree.Element.iter()

xml.etree.ElementTree.Element.getiterator() was deprecated since Python 3.2 and
dropped in Python 3.9

Fixes:
Verify sepolicy interface -c -i works ... Traceback (most recent call last):
  File "/usr/bin/sepolicy", line 691, in <module>
    args = parser.parse_args(args=parser_args)
  File "/usr/lib64/python3.9/argparse.py", line 1819, in parse_args
    args, argv = self.parse_known_args(args, namespace)
  File "/usr/lib64/python3.9/argparse.py", line 1852, in parse_known_args
    namespace, args = self._parse_known_args(args, namespace)
  File "/usr/lib64/python3.9/argparse.py", line 2043, in _parse_known_args
    positionals_end_index = consume_positionals(start_index)
  File "/usr/lib64/python3.9/argparse.py", line 2020, in consume_positionals
    take_action(action, args)
  File "/usr/lib64/python3.9/argparse.py", line 1929, in take_action
    action(self, namespace, argument_values, option_string)
  File "/usr/lib64/python3.9/argparse.py", line 1208, in __call__
    subnamespace, arg_strings = parser.parse_known_args(arg_strings, None)
  File "/usr/lib64/python3.9/argparse.py", line 1852, in parse_known_args
    namespace, args = self._parse_known_args(args, namespace)
  File "/usr/lib64/python3.9/argparse.py", line 2061, in _parse_known_args
    start_index = consume_optional(start_index)
  File "/usr/lib64/python3.9/argparse.py", line 2001, in consume_optional
    take_action(action, args, option_string)
  File "/usr/lib64/python3.9/argparse.py", line 1929, in take_action
    action(self, namespace, argument_values, option_string)
  File "/usr/bin/sepolicy", line 216, in __call__
    interface_dict = get_interface_dict()
  File "/usr/lib/python3.9/site-packages/sepolicy/interface.py", line 149, in get_interface_dict
    for i in m.getiterator('interface'):
AttributeError: 'xml.etree.ElementTree.Element' object has no attribute 'getiterator'

Signed-off-by: Petr Lautrbach <plautrba@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>

python/sepolicy/sepolicy/interface.py

@@ -146,12 +146,12 @@ def get_interface_dict(path="/usr/share/selinux/devel/policy.xml"):
             tree = xml.etree.ElementTree.fromstring(xml_path)
         for l in tree.findall("layer"):
             for m in l.findall("module"):
-                for i in m.getiterator('interface'):
+                for i in m.iter('interface'):
                     for e in i.findall("param"):
                         param_list.append(e.get('name'))
                     interface_dict[(i.get("name"))] = [param_list, (i.find('summary').text), "interface"]
                     param_list = []
-                for i in m.getiterator('template'):
+                for i in m.iter('template'):
                     for e in i.findall("param"):
                         param_list.append(e.get('name'))
                     interface_dict[(i.get("name"))] = [param_list, (i.find('summary').text), "template"]