Bug#677639: gnome-control-center: Network: Adding VPN fails silently if no VPN plugins could be found

[Alois Mahdal]

Package: gnome-control-center
Version: 1:3.4.2-2
Severity: normal

When I try to add VPN via gnome-control-center / Network (typically
accessing it via Gnome3 top bar's notification icon), action fails
silently with no explanation after clicking "+" (plus sign) and
"Create..." button in the next dialog.  (Main "Network" window is
not affected.)

Looking at STDERR, apparently problem is that I have no VPN plugins
installed:


    (gnome-control-center:30919): Gtk-WARNING **: Overriding tab label for notebook

    (gnome-control-center:30919): Gtk-WARNING **: Overriding tab label for notebook

    (gnome-control-center:30919): Gtk-WARNING **: Overriding tab label for notebook

    ** (nm-connection-editor:30924): WARNING **: vpn_ask_connection_type: no VPN plugins could be found!


There should be, however, explanation in the GUI why the action failed.

STR:

  0. Prerequisities:

     -- no VPN plug-ins installed

     -- Gnome 3

  1. Click network icon in notification area ov Gnome3 top bar

  2. Choose "Network Settings"

  3. Click "+" under the list of interfaces

     -- dialog to choose interface appears

  4. Choose "VPN" as Interface 

  5. Click "Create..."

     -- result: dialog to choose interface disappears

     -- oracle: dialog should not simply disappear; an explanation
                should be displayed or it should not be possible
                to reach this situation


-- System Information:
Debian Release: wheezy/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 3.0.0-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages gnome-control-center depends on:
ii  accountsservice            0.6.15-4
ii  apg                        2.2.3.dfsg.1-2
ii  desktop-file-utils         0.18-1
ii  gnome-control-center-data  1:3.4.2-2
ii  gnome-desktop3-data        3.4.2-1
ii  gnome-icon-theme           3.4.0-2
ii  gnome-icon-theme-symbolic  3.4.0-2
ii  gnome-menus                3.4.2-1
ii  gnome-settings-daemon      3.4.2-3
ii  gsettings-desktop-schemas  3.4.2-1
ii  libatk1.0-0                2.4.0-2
ii  libc6                      2.13-33
ii  libcairo-gobject2          1.12.2-1
ii  libcairo2                  1.12.2-1
ii  libcanberra-gtk3-0         0.28-4
ii  libcanberra0               0.28-4
ii  libcheese-gtk21            3.4.2-1
ii  libcheese3                 3.4.2-1
ii  libclutter-1.0-0           1.10.6-1
ii  libcogl-pango0             1.10.2-3
ii  libcogl9                   1.10.2-3
ii  libcolord1                 0.1.21-1
ii  libcomerr2                 1.42.2-2
ii  libcups2                   1.5.3-1
ii  libdbus-1-3                1.5.12-1
ii  libdbus-glib-1-2           0.98-1
ii  libfontconfig1             2.9.0-6
ii  libgcrypt11                1.5.0-3
ii  libgdk-pixbuf2.0-0         2.26.1-1
ii  libglib2.0-0               2.32.3-1
ii  libgnome-bluetooth10       3.4.0-2
ii  libgnome-desktop-3-2       3.4.2-1
ii  libgnome-menu-3-0          3.4.2-1
ii  libgnomekbd7               3.4.0.2-1
ii  libgnutls26                2.12.19-1
ii  libgoa-1.0-0               3.4.2-1
ii  libgssapi-krb5-2           1.10.1+dfsg-1
ii  libgstreamer0.10-0         0.10.36-1
ii  libgtk-3-0                 3.4.2-1
ii  libgtop2-7                 2.28.4-3
ii  libjson-glib-1.0-0         0.14.2-1
ii  libk5crypto3               1.10.1+dfsg-1
ii  libkrb5-3                  1.10.1+dfsg-1
ii  libnm-glib4                0.9.4.0-5
ii  libnm-gtk0                 0.9.4.1-1+b1
ii  libnm-util2                0.9.4.0-5
ii  libnotify4                 0.7.5-1
ii  libpango1.0-0              1.30.0-1
ii  libpolkit-gobject-1-0      0.105-1
ii  libpulse-mainloop-glib0    2.0-3
ii  libpulse0                  2.0-3
ii  libsocialweb-client2       0.25.20-1
ii  libupower-glib1            0.9.16-2
ii  libwacom2                  0.5-1
ii  libx11-6                   2:1.4.99.901-2
ii  libxcomposite1             1:0.4.3-2
ii  libxdamage1                1:1.1.3-2
ii  libxext6                   2:1.3.1-2
ii  libxfixes3                 1:5.0-4
ii  libxi6                     2:1.6.1-1
ii  libxklavier16              5.2.1-1
ii  libxml2                    2.8.0+dfsg1-3
ii  zlib1g                     1:1.2.7.dfsg-11

Versions of packages gnome-control-center recommends:
ii  cups-pk-helper         0.2.1.2-1
ii  gnome-online-accounts  3.4.2-1
ii  gnome-session          3.4.2.1-1
ii  gnome-user-guide       3.4.2-1
ii  iso-codes              3.35-1
ii  mesa-utils             8.0.1-2+b3
ii  mousetweaks            3.4.2-1
ii  policykit-1-gnome      0.105-2

Versions of packages gnome-control-center suggests:
ii  gnome-screensaver         3.4.1-1
ii  gstreamer0.10-pulseaudio  0.10.31-3
ii  libcanberra-gtk-module    0.28-4
ii  x11-xserver-utils         7.7~3
ii  xscreensaver              5.15-2

-- debconf-show failed