The "Add a VPN Connection" menu entry is disabled even with VPN plugins installed

[Stephen Kent]

I am on Linux Mint 18.2 with network-manger-gnome version 1.2.6-0ubuntu0.16.04.4.

Steps to reproduce:

- Install a VPN plugin (such as the package network-manager-openvpn-gnome)
- Click the network manager applet to open the menu
- Select the "VPN Connections" submenu
- Observe the "Add a VPN Connection" menu entry is disabled

Expected behavior: The "Add a VPN Connection" menu entry is enabled and works properly.

[Sebastien Bacher (seb128)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. The issue you are reporting is an upstream one and it would be nice if somebody having it could send the bug to the developers of the software by following the instructions at https://wiki.ubuntu.com/Bugs/Upstream/GNOME. If you have done so, please tell us the number of the upstream bug (or the link), so we can add a bugwatch that will inform us about its status. Thanks in advance.