use putIfAbsent and not put in Hazelcast client

Author: akuksin

spring-boot/hazelcast/hazelcast-client-server/src/main/java/io/reflectoring/cache/cleint/client/CacheClient.java

@@ -1,9 +1,6 @@
 package io.reflectoring.cache.cleint.client;
 
 import com.hazelcast.client.HazelcastClient;
-import com.hazelcast.client.config.ClientConfig;
-import com.hazelcast.config.Config;
-import com.hazelcast.config.MapConfig;
 import com.hazelcast.core.HazelcastInstance;
 import com.hazelcast.core.IMap;
 import io.reflectoring.cache.cleint.rest.Car;