[USB Drive Manager] icon not shown if drive already mounted

[simonjones49]

If a drive is mounted the plugin shows a black circle, I can then use the plugin as normal, or unmount everything and the icon appears.
This is how it shows if a drive is mounted at login

Then if I hover on the black circle I can see

This is especially bad for me as I use pam_usb to provide the login password and a USB device is always mounted at login.

[spiros132]

@hennifant

[Electronic-Mango]

I created a PR which solves this issue: #797