RFR: Add topological merge bot

[Jorn Vernee via github.com]

The pull request has been updated with additional changes.

----------------

Added commits:
 - 62d1e15f:	Fix resource leak

Pull request:
https://git.openjdk.java.net/skara/pull/105

Webrevs:
 - full: https://webrevs.openjdk.java.net/skara/105/webrev.05
 - inc: https://webrevs.openjdk.java.net/skara/105/webrev.04-05

Updated full patch:
https://git.openjdk.java.net/skara/pull/105.diff

Fetch command:
git fetch https://git.openjdk.java.net/skara pull/105/head:pull/105