JAVA-2044: In ServerMonitor reset currentException to null each time through the loop. This will ensure that a successful connection after a failed connection will be properly logged.

Author: jyemin

src/main/com/mongodb/ServerMonitor.java

@@ -83,6 +83,7 @@ public void run() {
                 while (!isClosed) {
                     ServerDescription previousServerDescription = currentServerDescription;
                     Throwable previousException = currentException;
+                    currentException = null;
                     try {
                         if (connection == null) {
                             connection = new DBPort(serverAddress, mongo, getOptions());