MINOR: mworker/cli: implement hard-reload over the master CLI

MINOR: mworker/cli: implement hard-reload over the master CLI

The mworker mode never had a proper 'hard-stop' (-st) for the reload,
this is a mode which was commonly used with the daemon mode, but it was
never implemented in mworker mode.

This patch fixes the problem by implementing a "hard-reload" command
over the master CLI. It does the same as the "reload" command, but
instead of waiting for the connections to stop in the previous process,
it immediately quits the previous process after binding.