[wishlist] Update manager: exit dialog window

[Álvaro Morán]

This problem happens If by accident you click on the x (close button on the top left corner) when an update is being done instead of minimise. The update-manager issues an error message when you open it again that the application didn't finish well.

I think that a way to solve this issue would be to have a dialog window that asks the user if what he wants to do is to exit and if yes, try to cancel the then current update.

lsb_release -rd
Description: Ubuntu 13.10
Release: 13.10

apt-cache policy update-manager
update-manager:
  Instalados: 1:0.194.1
  Candidato: 1:0.194.1
  Tabla de versión:
 *** 1:0.194.1 0
        500 http://ftp.free.org/mirrors/archive.ubuntu.com/ubuntu/ saucy-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     1:0.194 0
        500 http://ftp.free.org/mirrors/archive.ubuntu.com/ubuntu/ saucy/main amd64 Packages

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: update-manager 1:0.194.1
ProcVersionSignature: Ubuntu 3.11.0-13.20-generic 3.11.6
Uname: Linux 3.11.0-13-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
CurrentDmesg.txt:
 [ 29.457838] init: anacron main process (927) killed by TERM signal
 [ 31.365850] hda-codec: out of range cmd 3:5:707:fffffffc
Date: Fri Nov 15 14:20:04 2013
ExecutablePath: /usr/bin/update-manager
GsettingsChanges:
 b'com.ubuntu.update-manager' b'first-run' b'false'
 b'com.ubuntu.update-manager' b'launch-time' b'1384521357'
 b'com.ubuntu.update-manager' b'show-details' b'true'
 b'com.ubuntu.update-manager' b'window-height' b'744'
 b'com.ubuntu.update-manager' b'window-width' b'1301'
InstallationDate: Installed on 2013-10-24 (22 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
InterpreterPath: /usr/bin/python3.3
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=es
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=es_ES.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
UpgradeStatus: No upgrade log present (probably fresh install)