reverted: setting lastConnectionFailure to null

src/main/java/com/zaxxer/hikari/pool/PoolBase.java

@@ -313,6 +313,7 @@ abstract class PoolBase
 
          connection = (username == null) ? dataSource.getConnection() : dataSource.getConnection(username, password);
          setupConnection(connection);
+         lastConnectionFailure.set(null);
          return connection;
       }
       catch (Exception e) {