Remove dead KeepaliveInfo if it cannot be started

If KeepaliveInfo was created but cannot be started, current
design will only notify apps but not remove it from local
hashmap, which will cause unexpected behavior if someone
tries to iterate records and fire callbacks.

Bug: 122636283
Test: atest FrameworksNetTests
Change-Id: If4cb25a881dd3555f569c729f88741675f7f3bdf