bluetooth: Invalidate characteristics when disconnecting
Remove characteristics from attribute instance map when a device
disconnects or when disconnect is called. Check that the
characteristic is in the attribute instance map and reject if it isn't.
BUG=
654950
Committed:
https://crrev.com/35b0cbff31387ff3b69607850f5ccfe99e2d4817
Cr-Commit-Position: refs/heads/master@{#430788}