rerror=ignore was returning true from scsi_handle_rw_error but the callers were not
calling scsi_req_complete when rerror=ignore returns true (this is the correct thing
to do when true is returned after executing a passthrough command). Fix this by
calling it in scsi_handle_rw_error.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>