Propagate the error return value from get_indirect(). This bug was
introduced in commit 4d684832 ("vring: create a common function to parse
descriptors").
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>