Merge "Use IPV6_MIN_MTU from NetworkConstants in Ikev2Vpn" am: 75304108e7 am: 8f85ecd1f5 am: 6a1cb62078

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1512879

Change-Id: Id415ecdbf1509b9c2e1b3e50bb716e7368f83dfc