Merge changes from topic "revert-1556807-tombstone_proto-NRGSMJBETL"

* changes:
  Revert "tombstoned: switch from goto to RAII."
  Revert "tombstoned: make it easier to add more types of outputs."
  Revert "tombstoned: support for protobuf fds."
  Revert "libdebuggerd: add protobuf implementation."
  Revert "Fix build breakage."