replay: disable default snapshot for record/replay

This patch disables setting '-snapshot' option on by default
in record/replay mode. This is needed for creating vmstates in record
and replay modes.
Signed-off-by: NPavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Acked-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

vl.c

@@ -1203,7 +1203,7 @@ static void configure_blockdev(BlockdevOptionsQueue *bdo_queue,
         qapi_free_BlockdevOptions(bdo->bdo);
         g_free(bdo);
     }
-    if (snapshot || replay_mode != REPLAY_MODE_NONE) {
+    if (snapshot) {
         qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot,
                           NULL, NULL);
     }
@@ -3066,7 +3066,13 @@ int main(int argc, char **argv, char **envp)
                 drive_add(IF_PFLASH, -1, optarg, PFLASH_OPTS);
                 break;
             case QEMU_OPTION_snapshot:
-                snapshot = 1;
+                {
+                    Error *blocker = NULL;
+                    snapshot = 1;
+                    error_setg(&blocker, QERR_REPLAY_NOT_SUPPORTED,
+                               "-snapshot");
+                    replay_add_blocker(blocker);
+                }
                 break;
             case QEMU_OPTION_numa:
                 opts = qemu_opts_parse_noisily(qemu_find_opts("numa"),