DO NOT MERGE A few tests in DevicePolicyManagerTests added to knownfailures.

A few tests in DevicePoliyManagerTests, did caused the security settings to change to lock-screen (with an empty password) or the swipe-to-unlock impacting all subsequent CTS tests. Addding to knownfailures so that we can keep running other tests while debugging the problem.

Bug: 17496766
Change-Id: Ie6ef946a04a36ae6b0b4393e582553900641f272