Fix first run keep invoking on every startup

Author: benwoo1110

src/main/java/org/mvplugins/multiverse/inventories/MultiverseInventories.java

@@ -260,6 +260,7 @@ public void reloadConfig() {
                 }
 
                 inventoriesConfig.get().setFirstRun(false);
+                inventoriesConfig.get().save();
             }
             worldGroupManager.get().checkForConflicts()
                     .sendConflictIssue(commandManagerProvider.get().getConsoleCommandIssuer());