Simplify brew install hub

[scpeters]

Remove an outdated workaround (since Homebrew/brew#10689 was already merged) to see if that fixes failures in bottle building script.

https://build.osrfoundation.org/job/generic-release-homebrew_triggered_bottle_builder/label=osx_arm64_sonoma/1825/

16:51:27 + brew install hub
16:51:27 + grep -v 'warning: conflicting chdir during another chdir block'
16:51:29 ==> Fetching downloads for: hub
16:51:29 ✔︎ Bottle Manifest hub (2.14.2)
16:51:29 ✔︎ Bottle Manifest hub (2.14.2)
16:51:29 ✔︎ Bottle hub (2.14.2)
16:51:29 Error: A `brew install hub` process has already locked /opt/homebrew/Cellar/pkgconf.
16:51:29 Please wait for it to finish or terminate it to continue.

[scpeters]

this didn't help

https://build.osrfoundation.org/job/generic-release-homebrew_triggered_bottle_builder/1827/label=osx_arm64_sonoma/console

[scpeters]

this didn't help

https://build.osrfoundation.org/job/generic-release-homebrew_triggered_bottle_builder/1827/label=osx_arm64_sonoma/console

marked https://build.osrfoundation.org/computer/mac-six-arm.sonoma/ as offline for now, since it seems related to that specific machine