changes to support proxy configs

Author: diana-derose

oauth2-platform-api/src/main/java/com/intuit/oauth2/client/DiscoveryAPIClient.java

@@ -45,10 +45,16 @@ public class DiscoveryAPIClient {
 
 	private ProxyConfig proxyConfig;
 
+	//use this constructor to apply proxy configs
 	public DiscoveryAPIClient(ProxyConfig proxyConfig) {
 		this.proxyConfig = proxyConfig;
 	}
 
+	//for non proxy call, use this constructor
+	public DiscoveryAPIClient() {
+		this.proxyConfig = null;
+	}
+	
 	/**
 	 * Calls the Discovery Document API based on the the Environment provided and
 	 * returns an object with url’s for all the endpoints