qemu-char: Fix ID reuse after chardev-remove for qapi-based init

Commit 2c5f4882 introduced qapi-based character device initialization
as a new code path in qemu_chr_new_from_opts().  Unfortunately, it
failed to store parameter opts in the new chardev.  Therefore,
qemu_chr_delete() doesn't delete it.  Even though the device is gone,
its options linger, and any attempt to create another one with the
same ID fails.

Cc: qemu-stable@nongnu.org
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 1372339512-28149-1-git-send-email-armbru@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>