ensure SHUTDOWN_NOSAVE in Sentinel mode

- enforcing of SHUTDOWN_NOSAVE flag in one place to make it consitent
  when running in Sentinel mode

src/db.c

@@ -963,14 +963,6 @@ void shutdownCommand(client *c) {
             return;
         }
     }
-    /* When SHUTDOWN is called while the server is loading a dataset in
-     * memory we need to make sure no attempt is performed to save
-     * the dataset on shutdown (otherwise it could overwrite the current DB
-     * with half-read data).
-     *
-     * Also when in Sentinel mode clear the SAVE flag and force NOSAVE. */
-    if (server.loading || server.sentinel_mode)
-        flags = (flags & ~SHUTDOWN_SAVE) | SHUTDOWN_NOSAVE;
     if (prepareForShutdown(flags) == C_OK) exit(0);
     addReplyError(c,"Errors trying to SHUTDOWN. Check logs.");
 }

src/server.c

@@ -3680,6 +3680,15 @@ void closeListeningSockets(int unlink_unix_socket) {
 }
 
 int prepareForShutdown(int flags) {
+    /* When SHUTDOWN is called while the server is loading a dataset in
+     * memory we need to make sure no attempt is performed to save
+     * the dataset on shutdown (otherwise it could overwrite the current DB
+     * with half-read data).
+     *
+     * Also when in Sentinel mode clear the SAVE flag and force NOSAVE. */
+    if (server.loading || server.sentinel_mode)
+        flags = (flags & ~SHUTDOWN_SAVE) | SHUTDOWN_NOSAVE;
+
     int save = flags & SHUTDOWN_SAVE;
     int nosave = flags & SHUTDOWN_NOSAVE;