Fix location of Homebrew tap

With https://github.com/Homebrew/homebrew/commit/e07584e3fbdc88327bafe23b9c40c904d0fff0a1, the location of the Homebrew taps has been modified.  Consequently the local `scc merge` operation fails in the daily Homebrew job. This single commit should restore the job.
To test it, check the next occurence of the job is green.

Note: this PR will be rebased onto `develop` and `dev_4_4`.