Fix clashing version from boxpy and subcommands.

Currently, you could pass long version of '--version' option to either
boxpy itself and subcommands create and rebuild. With this patch proper
context is now detected.

box.py

@@ -1398,7 +1398,7 @@ def main():
 
     LOG.set_verbose(args.verbose, args.quiet)
 
-    if args.version:
+    if not getattr(args, 'func') and args.version:
         LOG.info(f'boxpy {__version__}')
         parser.exit()