When a serial device is disconnected the user receives two
dialog messages indicating there was a serial device error.
This can cause confusion since the error message does not
clearly indicate what has happened.
Instead of alerting the user this will push the message to the console.
When the plugin is already started we skip calling createDevicePlugin(),
which is fine except that we were relying on createDevicePlugin() to
call checkPolling() for us. We now call checkPolling() directly in those
cases where it was being skipped before.
