network_state: improve state comparison for achieving idempotency

`libnmstate.show()` would include the info like bridge timer etc which
should not be considered when comparing between the previous state and
current state. Instead, using the the `libnmstate.show_running_config()`
which would filter out these kind of data.

Signed-off-by: Wen Liang <liangwen12year@gmail.com>

library/network_state.py

@@ -39,12 +39,12 @@ class NetworkState:
         self.params = module.params
         self.result = dict(changed=False)
         self.module_name = module_name
-        self.previous_state = libnmstate.show()
+        self.previous_state = self.get_state_config()
 
     def run(self):
         desired_state = self.params["desired_state"]
         libnmstate.apply(desired_state)
-        current_state = libnmstate.show()
+        current_state = self.get_state_config()
         if current_state != self.previous_state:
             self.result["changed"] = True
 
@@ -52,6 +52,15 @@ class NetworkState:
 
         self.module.exit_json(**self.result)
 
+    def get_state_config(self):
+        if hasattr(libnmstate, "show_running_config") and callable(
+            getattr(libnmstate, "show_running_config")
+        ):
+            state_config = libnmstate.show_running_config()
+        else:
+            state_config = libnmstate.show()
+        return state_config
+
 
 def run_module():
     module_args = dict(