Multiple bottle build jobs triggered by single comment

[scpeters]

The osrf/homebrew-simulation repository uses GitHub comments to trigger bottle building CI jobs. Recently I noticed that a single comment osrf/homebrew-simulation#2143 (comment) triggered two bottle builder jobs:

• https://build.osrfoundation.org/job/generic-release-homebrew_triggered_bottle_builder/1058/
• https://build.osrfoundation.org/job/generic-release-homebrew_triggered_bottle_builder/1059/

I've never seen this happen before. Both jobs finished and uploaded their bottles, and the latter one overwrote the first set of bottles. Everything is fine, but it was weird and I wanted to note that it happened.