Bug#661062: python-apt: del apt_pkg.config[keyword] segfaults

[Jakub Wilk <jwilk@debian.org>]

Package: python-apt
Version: 0.8.3+nmu1

$ python -c 'import apt_pkg as a; a.init(); del a.config["Acquire::cdrom"]'
Segmentation fault


Backtrace:
#0  0xf7b2747b in CnfMapSet (Self=<apt_pkg.Configuration at remote 0xf7b5d9b0>, Arg='Acquire::cdrom', Val=0x0) at python/configuration.cc:334
#1  0x08103c75 in PyObject_DelItem ()
#2  0x0814e01d in PyEval_EvalFrameEx ()
#3  0x081518a0 in PyEval_EvalCodeEx ()
#4  0x0814b0c5 in PyRun_StringFlags ()
#5  0x08195c07 in Py_Main ()
#6  0x08060ffb in main ()


-- System Information:
Debian Release: wheezy/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: i386 (i686)

Kernel: Linux 3.2.0-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)
Shell: /bin/sh linked to /bin/dash

Versions of packages python-apt depends on:
ii  apt [libapt-pkg4.10]        0.8.15.9
ii  apt-utils [libapt-inst1.2]  0.8.15.9
ii  libc6                       2.13-26
ii  libgcc1                     1:4.6.2-15
ii  libstdc++6                  4.6.2-15
ii  python                      2.7.2-10
ii  python-apt-common           0.8.3+nmu1
ii  python2.6                   2.6.7-4
ii  python2.7                   2.7.2-13

Versions of packages python-apt recommends:
ii  iso-codes    3.32.2-1
ii  lsb-release  3.2-28.1
ii  python2.6    2.6.7-4
ii  xz-lzma      5.1.1alpha+20110809-3

Versions of packages python-apt suggests:
pn  python-apt-dbg  0.8.3+nmu1
pn  python-apt-doc  <none>
pn  python-gtk2     <none>
pn  python-vte      <none>

--
Jakub Wilk