qemuSnapshotDiskContextNew: Don't set 'ndd'

'ndd' tracks the actual number of snapshot disks filled into the
structure and is incremented by the functions filling the context, thus
it must not be set when initializing the context.

Fixes: 8c2ecdf131c
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

src/qemu/qemu_snapshot.c

@@ -865,7 +865,6 @@ qemuSnapshotDiskContextNew(size_t ndisks,
     qemuSnapshotDiskContextPtr ret = g_new0(qemuSnapshotDiskContext, 1);
 
     ret->dd = g_new0(qemuSnapshotDiskData, ndisks);
-    ret->ndd = ndisks;
     ret->actions = virJSONValueNewArray();
     ret->vm = vm;
     ret->asyncJob = asyncJob;