[automerger skipped] Modify javadoc for some extra values of VpnManager event...

[automerger skipped] Modify javadoc for some extra values of VpnManager event am: bf3953a6 -s ours

am skip reason: Merged-In I7fd4b6dad1a4363336f03c217e635fc45bcd0ab6 with SHA-1 4b6b7987 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18112115



Change-Id: Ib6e25276457c4c3178c1e4470a21639c12143b64
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>