Fix copyright headers

[ntolia]

While the top-level license file is Apache 2.0, a number of the source code files say

/*******************************************************************************
 * IBM Confidential
 * OCO Source Materials
 * IBM Cloud Container Service, 5737-D43
 * (C) Copyright IBM Corp. 2018 All Rights Reserved.
 * The source code for this program is not  published or otherwise divested of
 * its trade secrets, irrespective of what has been deposited with
 * the U.S. Copyright Office.
 ******************************************************************************/

Can we remove this so that there is no licensing confusion for users of this library?

[akgunjal]

@arahamad : We can remove IBM license from all source code files as the open source only has apache license now.