cc_vyos: T6007: Run config migrations before Cloud-init

Configuration in `vyos_config_commands` is expected to use a syntax from the
target VyOS version. But, if Cloud-init applies configuration commands to a
default file, all the migrations (from the 0 version to the latest) will still
be executed on top of it.

This process can break proper config, for example, if the current syntax variant
partially repeats one of the older ones, which will trigger a migration without
need.

cloudinit/config/cc_vyos.py

@@ -1081,6 +1081,10 @@ def handle(name, cfg, cloud, log, _args):
         file_name = cfg_file_name
 
     logger.debug("Using configuration file: {}".format(file_name))
+    # We must run all migrations on the config before Cloud-init will modify it
+    # Otherwise, regardless of proper syntax for the current version, migrations will be re-run with unpredictable result
+    logger.debug("Running migrations for: {}".format(file_name))
+    run(['/usr/libexec/vyos/run-config-migration.py', file_name])
     with open(file_name, 'r') as f:
         config_file = f.read()
     config = ConfigTree(config_file)