Fix update check issue in junos_config (ansible#20182)

* Fix update check issue in junos_config and required_if enhancement

* Add additional check to update argument which will ensure config
  statement is present.
* Add 'or' condition support in 'required_if'.

* Fix python 2.4 syntax issue

* revert requied_if changes

lib/ansible/modules/network/junos/junos_config.py

@@ -346,9 +346,9 @@ def main():
                           ('update', 'replace')]
 
     required_if = [('replace', True, ['src']),
-                   ('update', 'merge', ['src']),
-                   ('update', 'overwrite', ['src']),
-                   ('update', 'replace', ['src'])]
+                   ('update', 'merge', ('src', 'lines')),
+                   ('update', 'overwrite', ('src', 'lines')),
+                   ('update', 'replace', ('src', 'lines'))]
 
     module = NetworkModule(argument_spec=argument_spec,
                            mutually_exclusive=mutually_exclusive,