crash in dbus metadata notifier for corrupted (?) UTF-8 strings

On Fedora18, with a mp3-in-flv media file, the libdbus abort()'s the vlc process due to perceived indiscretions about the UTF-8 content.

% gdb -args /usr/bin/vlc horrid.flv
(gdb) run
process 12003: arguments to dbus_message_iter_append_basic() were incorrect, assertion "_dbus_check_is_valid_utf8 (*string_p)" failed in file dbus-message.c line 2598.
This is normally a bug in some application using the D-Bus library.
  D-Bus not built with -rdynamic so unable to print a backtrace

Program received signal SIGABRT, Aborted.
[Switching to Thread 0x2aaab2538700 (LWP 12018)]
0x00000030c4435ba5 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:63
63	  return INLINE_SYSCALL (tgkill, 3, pid, selftid, sig);
(gdb) bt
[#0](https://code.videolan.org/videolan/vlc/-/issues/0)  0x00000030c4435ba5 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:63
[#1](https://code.videolan.org/videolan/vlc/-/issues/1)  0x00000030c4437358 in __GI_abort () at abort.c:90
[#2](https://code.videolan.org/videolan/vlc/-/issues/2)  0x00000030cb430ab5 in _dbus_abort () at dbus-sysdeps.c:94
[#3](https://code.videolan.org/videolan/vlc/-/issues/3)  0x00000030cb427545 in _dbus_warn_check_failed (
    format=0x30cb436ee0 "arguments to %s() were incorrect, assertion \"%s\" failed in file %s line %d.\nThis is normally a bug in some application using the D-Bus library.\n") at dbus-internals.c:290
[#4](https://code.videolan.org/videolan/vlc/-/issues/4)  0x00000030cb419c86 in dbus_message_iter_append_basic (value=0x2aaab2537908, type=115, iter=0x2aaab25379b0) at dbus-message.c:2598
[#5](https://code.videolan.org/videolan/vlc/-/issues/5)  dbus_message_iter_append_basic (iter=iter@entry=0x2aaab25379b0, type=type@entry=115, value=value@entry=0x2aaab2537908) at dbus-message.c:2578
[#6](https://code.videolan.org/videolan/vlc/-/issues/6)  0x00002aaab212dbf1 in GetInputMeta (p_input=0x6f9a10, args=args@entry=0x2aaab2537c40) at dbus.c:1159
[#7](https://code.videolan.org/videolan/vlc/-/issues/7)  0x00002aaab212feee in PropertiesChangedSignal (p_intf=0x6e1838, p_changed_properties=0x2aaab2537e40) at dbus_player.c:904
[#8](https://code.videolan.org/videolan/vlc/-/issues/8)  0x00002aaab21316e9 in PlayerPropertiesChangedEmit (p_intf=p_intf@entry=0x6e1838, p_changed_properties=p_changed_properties@entry=0x2aaab2537e40)
    at dbus_player.c:996
[#9](https://code.videolan.org/videolan/vlc/-/issues/9)  0x00002aaab212ac09 in ProcessEvents (i_events=-1303151304, p_events=0x2aaab2537d30, p_intf=0x6e1838) at dbus.c:586
[#10](https://code.videolan.org/videolan/vlc/-/issues/10) Run (p_intf=0x6e1838) at dbus.c:838
[#11](https://code.videolan.org/videolan/vlc/-/issues/11) 0x00000030c602c1da in RunInterface (p_this=<optimized out>) at interface/interface.c:229

(gdb) frame 4
[#4](https://code.videolan.org/videolan/vlc/-/issues/4)  0x00000030cb419c86 in dbus_message_iter_append_basic (value=0x2aaab2537908, type=115, iter=0x2aaab25379b0) at dbus-message.c:2598
2598	        _dbus_return_val_if_fail (_dbus_check_is_valid_utf8 (*string_p), FALSE);
(gdb) p * string_p
$1 = 0xab2400 "\301\326\303\356\277", <incomplete sequence \311>
(gdb) 
(gdb) frame 6
[#6](https://code.videolan.org/videolan/vlc/-/issues/6)  0x00002aaab212dbf1 in GetInputMeta (p_input=0x6f9a10, args=args@entry=0x2aaab2537c40) at dbus.c:1159
1159	    ADD_VLC_META_STRING( 3,  Artist );

Now, considering the horrid nature of the attached flv file, I can't call it an "artist" with a capital A. But at least vlc/dbus shouldn't have a cow about it.