AOF & RDB: be compatible with rdbchecksum no

src/rdb.c

@@ -1649,16 +1649,18 @@ int rdbLoadRio(rio *rdb, rdbSaveInfo *rsi) {
         decrRefCount(key);
     }
     /* Verify the checksum if RDB version is >= 5 */
-    if (rdbver >= 5 && server.rdb_checksum) {
+    if (rdbver >= 5) {
         uint64_t cksum, expected = rdb->cksum;
 
         if (rioRead(rdb,&cksum,8) == 0) goto eoferr;
-        memrev64ifbe(&cksum);
-        if (cksum == 0) {
-            serverLog(LL_WARNING,"RDB file was saved with checksum disabled: no check performed.");
-        } else if (cksum != expected) {
-            serverLog(LL_WARNING,"Wrong RDB checksum. Aborting now.");
-            rdbExitReportCorruptRDB("RDB CRC error");
+        if (server.rdb_checksum) {
+            memrev64ifbe(&cksum);
+            if (cksum == 0) {
+                serverLog(LL_WARNING,"RDB file was saved with checksum disabled: no check performed.");
+            } else if (cksum != expected) {
+                serverLog(LL_WARNING,"Wrong RDB checksum. Aborting now.");
+                rdbExitReportCorruptRDB("RDB CRC error");
+            }
         }
     }
     return C_OK;