ZOOKEEPER-3194: Quorum TLS - fix copy/paste bug in ZKTrustManager

Fix an obvious copy/paste bug. Tested by making sure ZKTrustManagerTest still passes.

Author: Ilya Maykov <ilyam@fb.com>

Reviewers: andor@apache.org

Closes #709 from ivmaykov/ZOOKEEPER-3194

zookeeper-server/src/main/java/org/apache/zookeeper/common/ZKTrustManager.java

@@ -85,7 +85,7 @@ public class ZKTrustManager extends X509ExtendedTrustManager {
 
     @Override
     public void checkClientTrusted(X509Certificate[] chain, String authType, SSLEngine engine) throws CertificateException {
-        x509ExtendedTrustManager.checkServerTrusted(chain, authType, engine);
+        x509ExtendedTrustManager.checkClientTrusted(chain, authType, engine);
         if (clientHostnameVerificationEnabled) {
             try {
                 performHostVerification(InetAddress.getByName(engine.getPeerHost()), chain[0]);