Fix a bug regarding layout-unable Scroll in CANotifyOnBootActivity Class.

Bug: 13591465

If we test "CA Cert Notification on Boot test" in Low-Density Device such as ldpi,
There are no place to display all texts and buttons-"Pass", "Info" and "Fail".
So we cannot finish and check this test.

I added a ScrollView as a root element to avoid that.

SIgned-off-by : Seunghyun Kim <mcseunghyun.kim@lge.com>

Change-Id: Ib1cfc5820561664f2a9c758a92328db9c40718ee