Merge "Expose AppOpsManager#OPSTR_ACTIVATE_PLATFORM_VPN as system API" am: 01bec3bb2b am: b8eb5b0ee1 am: b892146fb4

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1484021

Change-Id: Ibe2ed0ef2cf3e2c654c8a1fca8dc045fc2666f08