Add change-abandoned hook for gerrit in puppet

Gerrit manifest for review servers was lacking
the change-abandoned hook, even though jeepyb had
already support for notifying LP bug when the linked
review was being abandoned.
This change adds the missing hook to the gerrit manifest
as a file resource.

Closes-Bug: 1319305
Change-Id: I07555bfbfe255239ab1aeaa5d14bcfa807005faf
Merge "Add change-abandoned hook for gerrit in puppet"