fix(userspace): remove unread variable in restart_handler

When hitting that part, the restart signal is triggered and the code
leaves the loop, hence setting should_restart as false makes no sense
in this context.

Signed-off-by: Samuel Gaist <samuel.gaist@idiap.ch>

userspace/falco/app/restart_handler.cpp

@@ -158,7 +158,6 @@ void falco::app::restart_handler::watcher_loop() noexcept
             // at least we don't make users wait for the timeout.
             if (should_restart)
             {
-                should_restart = false;
                 // todo(jasondellaluce): make this a callback too maybe?
                 g_restart_signal.trigger();
                 return;