crash when no permission to read preferences.xml

[Rwst]

On Ubuntu with cvs and 0.43:
Regardless of content of preferences.xml, if that file is
not readable then inkscape will crash with

#0 0xb71d24b0 in fread () from /lib/tls/i686/cmov/libc.so.6
#1 0x083e276d in XmlSource::read (this=0xbfdbd8d4, buffer=0x8634708 "",
len=4000)
    at xml/repr-io.cpp:132
#2 0xb7729d7f in xmlParserInputBufferGrow () from /usr/lib/libxml2.so.2
#3 0xb77036e4 in xmlParserInputGrow () from /usr/lib/libxml2.so.2
#4 0xb7706e6b in xmlPopInput () from /usr/lib/libxml2.so.2
#5 0xb771a8ee in xmlParseDocument () from /usr/lib/libxml2.so.2
#6 0xb771b63b in xmlCtxtResetPush () from /usr/lib/libxml2.so.2
#7 0x083e3435 in sp_repr_read_file (
    filename=0x8637220 "/home/ralf/.inkscape/preferences.xml",
default_ns=0x0)
    at xml/repr-io.cpp:239
#8 0x0807d37e in inkscape_load_config (filename=0x8405ddb
"preferences.xml",
    config=0x85edfa4,
    skeleton=0x8403a00 "<inkscape version=\"0.43+devel\"\n
xmlns:sodipodi=\"http://inkscape.sourceforge.net/DTD/sodipodi-0.dtd\"\n
xmlns:inkscape=\"http://www.inkscape.org/namespaces/inkscape\">\n <group
id=\"window\">\n <group id"...,
    skel_size=9063, e_notreg=0x8402f51 "%s is not a regular file.\n%s",
    e_notxml=0x840327c "%s not a valid XML file, or\nyou don't have read
permissions on it.\n%s", e_notsp=0x8405db4 "%s is not a valid preferences
file.\n%s",
    warn=0x8405d68 "Inkscape will run with default settings.\nNew settings
will not be saved.") at inkscape.cpp:655
#9 0x08083b2e in Inkscape::Preferences::load () at preferences.cpp:53
#10 0x0807d8bb in inkscape_application_init (
    argv0=0xbfdbfbca "/mnt/inkscape-cvs-trunk/src/inkscape", use_gui=1)
    at inkscape.cpp:582
#11 0x08070330 in sp_main_gui (argc=1, argv=0xbfdbdb04) at main.cpp:810
#12 0x08167340 in Inkscape::NSApplication::Application::run
(this=0xbfdbda58)
    at application/application.cpp:121
#13 0x0806fb99 in main (argc=1, argv=0xbfdbdb04) at main.cpp:669

[Cth103 (cth103)]

Fixed in SVN.