Prevent race condition in replication of configuration

Temporary files may be removed while the configuration is being
synchronized. This could lead to sporadic FileNotFoundError exceptions
which our system level tests stumbled upon every now and then.

How it could look like:

```
FileNotFoundError: [Errno 2] No such file or directory: '/omd/sites/int_test/var/check_mk/web/automation/.last_login.mk.new5lqntxh5'a
```

The replication code now deals better with such situations by catching
the exceptions and skipping the file in question.

Change-Id: Iaeaab4b4a2f4753c0268795cfccce1852898b9c8

cmk/gui/watolib/activate_changes.py

@@ -2067,17 +2067,20 @@ def _get_replication_dir_config_sync_file_infos_per_inode(
 
         for dir_name in dir_names:
             dir_path = os.path.join(root, dir_name)
-            if (
-                os.path.exists(dir_path)
-                and os.path.islink(dir_path)
-                and not dir_name == GENERAL_DIR_EXCLUDE
-            ):
-                inode_sync_states[os.stat(dir_path).st_ino] = _get_config_sync_file_info(dir_path)
+            try:
+                if os.path.islink(dir_path) and not dir_name == GENERAL_DIR_EXCLUDE:
+                    inode_sync_states[os.stat(dir_path).st_ino] = _get_config_sync_file_info(
+                        dir_path
+                    )
+            except FileNotFoundError:
+                pass  # Ignore directories vanishing during processing
 
         for file_name in file_names:
             file_path = os.path.join(root, file_name)
-            if os.path.exists(file_path):
+            try:
                 inode_sync_states[os.stat(file_path).st_ino] = _get_config_sync_file_info(file_path)
+            except FileNotFoundError:
+                pass  # Ignore files vanishing during processing
 
 
 def _prepare_for_activation_tasks(