Wrong Disk size reported in "About this computer"

Wrong Disk size reported in "About this computer"

to reproduce this bug and look into it:

1. encrypt /dev/sda2/ extended and create the encrypted /dev/sda5

2. check Disk size reported in "About this computer"

3. the dusk size reported is the sum of sda2 and sda5 although it's actually just sda2 that has "real" size

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: chromium-browser 30.0.1599.114-0ubuntu0.13.10.2
ProcVersionSignature: Ubuntu 3.11.0-13.20-generic 3.11.6
Uname: Linux 3.11.0-13-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
Date: Mon Nov 11 13:05:18 2013
Desktop-Session:
 DESKTOP_SESSION = ubuntu
 XDG_CONFIG_DIRS = /etc/xdg/xdg-ubuntu:/usr/share/upstart/xdg:/etc/xdg
 XDG_DATA_DIRS = /usr/share/ubuntu:/usr/share/gnome:/usr/local/share/:/usr/share/
DetectedPlugins: (no entry found in the Preferences file)
EcryptfsInUse: Yes
Env:
 MOZ_PLUGIN_PATH = None
 LD_LIBRARY_PATH = None
ExecutablePath: /usr/lib/chromium-browser/chromium-browser
MarkForUpload: True
SourcePackage: chromium-browser
UpgradeStatus: No upgrade log present (probably fresh install)
chromium-default: CHROMIUM_FLAGS=""
gconf-keys: /desktop/gnome/applications/browser/exec = b'/usr/bin/chromium-browser\n'/desktop/gnome/url-handlers/https/command = b'/usr/bin/chromium-browser %s\n'/desktop/gnome/url-handlers/https/enabled = b'true\n'/desktop/gnome/url-handlers/http/command = b'/usr/bin/chromium-browser %s\n'/desktop/gnome/url-handlers/http/enabled = b'true\n'/desktop/gnome/session/required_components/windowmanager = b''/apps/metacity/general/compositing_manager = b''/desktop/gnome/interface/icon_theme = b'gnome\n'/desktop/gnome/interface/gtk_theme = b'Clearlooks\n'