When a remote MODRESTART command is received, it will pass through the

When a remote MODRESTART command is received, it will pass through the
ENCAP module. The ms_encap function is responsible for dispatching the
command handler and then the modules will eventually be reloaded.

However, if the ENCAP module is reloaded to a different address, the
stack now contains the address of a function that no longer exists.

Also, in this version of the IRCd, the module restarting functionality
was located in a function that is itself located in a module, so things
will also go badly if that module is reloaded to a different address,
too.

Return immediately from the command handler and have the event loop
call the function responsible for reloading the modules instead.

c.f. release/3.5 commit db05a3621058

Reported-by: mniip (Freenode)