Merge "Keystore 2.0: Add @IntDef for Keystore namespaces." am: faabd1a836 am: 15d9a3ab42

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1649668

Change-Id: I2b03db7d4300d2011db7a9685aafc1091f752465