qemu: Add missing encinfo cleanup

When commit id 'da86c6c2' added support for diskPriv->encinfo in
qemuDomainSecretDiskPrepare a change to qemuDomainSecretDiskDestroy
to was missed. Although qemuDomainDiskPrivateDispose probably would
do the trick.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

src/qemu/qemu_domain.c

@@ -1302,10 +1302,11 @@ qemuDomainSecretDiskDestroy(virDomainDiskDefPtr disk)
 {
     qemuDomainDiskPrivatePtr diskPriv = QEMU_DOMAIN_DISK_PRIVATE(disk);
 
-    if (!diskPriv || !diskPriv->secinfo)
-        return;
+    if (diskPriv && diskPriv->secinfo)
+        qemuDomainSecretInfoFree(&diskPriv->secinfo);
 
-    qemuDomainSecretInfoFree(&diskPriv->secinfo);
+    if (diskPriv && diskPriv->encinfo)
+        qemuDomainSecretInfoFree(&diskPriv->encinfo);
 }