External Drives should not send notifications on SD card detection

[Alexey Kulik]

External Drives application sends notification "Storage device detected. This device will be scanned for new content" for SD card each time the device turns on. SD card is a kind of device's internal memory. Generally, it is rarely removed or inserted back again. Sending notifications in this case does not bring any new information, it is annoying and distracting from actual notifications important for the user.
I propose disabling the notifications for SD cards.

[Anupam (anupam207)]

Possible duplicate of bug #1518124

[Anupam (anupam207)]

Workaround: There is a toggle switch for "External Drives" at System Settings > Notifications. Turning it off gets rid of these notifications. The state of this switch is persistent across reboots.

[Alexey Kulik (doctor-rover)]

@Anupam Thank you. It's definitely a duplicate. Sorry, I missed it. I will mark this one as a duplicate.
Concerning your workaround, it's not working now. It used to work before, but it hasn't been working for about a month. If you explicitly turn off notifications for "External Drives" in System Settings > Notifications _now_, the notifications from this app will still be sent. This looks like a bug.
I'm on rc-proposed/r162.