chardev: don't abort on attempt to add duplicated chardev
This is a regression from commit
d2623129a7d ("qom: Drop parameter @errp
of object_property_add() & friends").
(qemu) chardev-add id=null,backend=null
(qemu) chardev-add id=null,backend=null
Unexpected error in object_property_try_add() at /home/elmarco/src/qemu/qom/object.c:1166:
attempt to add duplicate property 'null' to object (type 'container')
That case is currently not covered in the test suite, but will be with
the queued patch "char: fix use-after-free with dup chardev &
reconnect".
Fixes:
d2623129a7dec1d3041ad1221dda1ca49c667532
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>