virtio-scsi: Plug memory leak on virtio_scsi_push_event() error path

Spotted by Coverity.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/scsi/virtio-scsi.c

diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index b0d7517..91a62ce 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -489,7 +489,7 @@
                                    uint32_t event, uint32_t reason)
 {
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
-    VirtIOSCSIReq *req = virtio_scsi_pop_req(s, vs->event_vq);
+    VirtIOSCSIReq *req;
     VirtIOSCSIEvent *evt;
     VirtIODevice *vdev = VIRTIO_DEVICE(s);
     int in_size;
@@ -498,6 +498,7 @@
         return;
     }
 
+    req = virtio_scsi_pop_req(s, vs->event_vq);
     if (!req) {
         s->events_dropped = true;
         return;