Do not active expire keys in the background when the switch is off.

src/server.c

@@ -1000,10 +1000,12 @@ void clientsCron(void) {
 void databasesCron(void) {
     /* Expire keys by random sampling. Not required for slaves
      * as master will synthesize DELs for us. */
-    if (server.active_expire_enabled && server.masterhost == NULL) {
-        activeExpireCycle(ACTIVE_EXPIRE_CYCLE_SLOW);
-    } else if (server.masterhost != NULL) {
-        expireSlaveKeys();
+    if (server.active_expire_enabled) {
+        if (server.masterhost == NULL) {
+            activeExpireCycle(ACTIVE_EXPIRE_CYCLE_SLOW);
+        } else {
+            expireSlaveKeys();
+        }
     }
 
     /* Defrag keys gradually. */