qemu: Fix segmentation fault when attaching a non iSCSI host device

Add a check if it's a iSCSI hostdev and if it's not then don't use the
union member 'iscsi'. The segmentation fault occured when accessing
secinfo->type, but this can vary from case to case.
Signed-off-by: NMarc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: NBjoern Walk <bwalk@linux.vnet.ibm.com>
Reviewed-by: NBoris Fiuczynski <fiuczy@linux.vnet.ibm.com>

src/qemu/qemu_hotplug.c

@@ -2343,8 +2343,6 @@ qemuDomainAttachHostSCSIDevice(virConnectPtr conn,
     bool secobjAdded = false;
     virJSONValuePtr secobjProps = NULL;
     virDomainHostdevSubsysSCSIPtr scsisrc = &hostdev->source.subsys.u.scsi;
-    virDomainHostdevSubsysSCSIiSCSIPtr iscsisrc = &scsisrc->u.iscsi;
-    qemuDomainStorageSourcePrivatePtr srcPriv;
     qemuDomainSecretInfoPtr secinfo = NULL;
 
     if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE_SCSI_GENERIC)) {
@@ -2386,9 +2384,12 @@ qemuDomainAttachHostSCSIDevice(virConnectPtr conn,
     if (qemuDomainSecretHostdevPrepare(conn, priv, hostdev) < 0)
         goto cleanup;
 
-    srcPriv = QEMU_DOMAIN_STORAGE_SOURCE_PRIVATE(iscsisrc->src);
-    if (srcPriv)
+    if (scsisrc->protocol == VIR_DOMAIN_HOSTDEV_SCSI_PROTOCOL_TYPE_ISCSI) {
+        qemuDomainStorageSourcePrivatePtr srcPriv =
+            QEMU_DOMAIN_STORAGE_SOURCE_PRIVATE(scsisrc->u.iscsi.src);
         secinfo = srcPriv->secinfo;
+    }
+
     if (secinfo && secinfo->type == VIR_DOMAIN_SECRET_INFO_TYPE_AES) {
         if (qemuBuildSecretInfoProps(secinfo, &secobjProps) < 0)
             goto cleanup;