XmlConfigBuilder: Near cache in-memory format can not be configured through XML file

Hi,

configuring the near cache in-memory format through a XML file does not work.

The problem is that the near cache uses reflection to configure itself. While looking for the method to invoke, the wrong method is choosen in NearCacheConfig. There are two methods with the same name, but having different argument types. If the method with the wrong argument type is selected, it will not be invoked.

Those are the two methods in question:

```java
NearCacheConfig.setInMemoryFormat(InMemoryFormat)
NearCacheConfig.setInMemoryFormat(String)
```

This pull request fixes the problem and the code below shows how to reproduce the issue.

Cheers,
Lukas

```java
package com.nm.test.hazelcast.config;

import com.hazelcast.config.*;
import com.nm.test.hazelcast.TestHazelcast;
import org.apache.log4j.BasicConfigurator;
import java.io.BufferedOutputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import junit.framework.TestCase;

/**
 * A test to ensure near-cache in-memory-format can be set through XML config.
 */
public class TestConfig1 extends TestCase {

	@Override
	protected void setUp() throws Exception {

		// configure logging
		if (!TestHazelcast.loggingInitialized) {
			TestHazelcast.loggingInitialized = true;
			BasicConfigurator.configure();
		}
	}

	public void testNearCacheConfig() throws Exception {

		// configure Log4j logging
		System.setProperty("hazelcast.logging.type", "log4j");

		// prepare config file
		String configPath = "/tmp/hazelcast-test-config1.xml";
		InputStream in = this.getClass().getResourceAsStream("hazelcast-test-config1.xml");
		OutputStream out = new BufferedOutputStream(new FileOutputStream(configPath));
		int next = -1;
		while ((next = in.read()) != -1) {
			out.write(next);
		}
		in.close();
		out.close();
		System.setProperty("hazelcast.config", configPath);

		// create hazelcast config
		Config config = new XmlConfigBuilder().build();

		// test near-cache in-memory-format setting
		MapConfig mapConfig = config.getMapConfig("testMapConfig1");
		NearCacheConfig ncConfig = mapConfig.getNearCacheConfig();
		if (!ncConfig.getInMemoryFormat().equals(InMemoryFormat.OBJECT)) {
			fail("Near cache config in-memory-format not set.");
		}
	}

}
```

and the test config file:

```
<?xml version="1.0" encoding="UTF-8"?>
<hazelcast xsi:schemaLocation="http://www.hazelcast.com/schema/config hazelcast-config-3.2.xsd"
           xmlns="http://www.hazelcast.com/schema/config"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <group>
        <name>dev</name>
        <password>dev-pass</password>
    </group>
    <management-center enabled="false">http://localhost:8080/mancenter</management-center>
    <network>
        <port auto-increment="true" port-count="100">5701</port>
        <outbound-ports>
            <!--
            Allowed port range when connecting to other nodes.
            0 or * means use system provided port.
            -->
            <ports>0</ports>
        </outbound-ports>
        <join>
            <multicast enabled="true">
                <multicast-group>224.2.2.3</multicast-group>
                <multicast-port>54327</multicast-port>
            </multicast>
            <tcp-ip enabled="false">
                <interface>127.0.0.1</interface>
            </tcp-ip>
        </join>
        <interfaces enabled="false">
            <interface>10.10.1.*</interface>
        </interfaces>
        <ssl enabled="false" />
        <socket-interceptor enabled="false" />
    </network>
    <partition-group enabled="false"/>
    <executor-service name="default">
        <pool-size>8</pool-size>
        <queue-capacity>0</queue-capacity>
    </executor-service>
    <map name="testMapConfig1">
        <near-cache>
            <in-memory-format>OBJECT</in-memory-format>
        </near-cache>
    </map>
</hazelcast>
```