qemuBlockBitmapsHandleCommitStart: Fix allocation of string list

Allocate space also for the terminating NULL.
Reported-by: NDaniel P. Berrangé <berrange@redhat.com>
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>
Tested-by: NDaniel P. Berrangé <berrange@redhat.com>

src/qemu/qemu_block.c

@@ -3021,7 +3021,7 @@ qemuBlockBitmapsHandleCommitStart(virStorageSourcePtr topsrc,
     if (!(entry = virHashLookup(blockNamedNodeData, basesrc->nodeformat)))
         return 0;
 
-    bitmaplist = g_new0(char *, entry->nbitmaps);
+    bitmaplist = g_new0(char *, entry->nbitmaps + 1);
 
     for (i = 0; i < entry->nbitmaps; i++) {
         qemuBlockNamedNodeDataBitmapPtr bitmap = entry->bitmaps[i];