Add the require boilerplate

Fixes a bug that sometimes comes up with load order on this module. I
know @jlee-r7 is working on a better overall solution but this should
solve for the short term. I'm happy to race.

Note, since the problem is practically machine-specific. @jlee-r7
suggested rm'ing all modules but the one under test. Doing that exposes
the bug, and I've verified this fix in that way.

### Verification

  - [ ] `rm -rf modules/exploits/* modules/auxiliary/* modules/post/*`
  - [ ] `git checkout upstream/pr/2303 modules/exploits/osx/local/sudo_password_bypass.rb`
  - [ ] `./msfcli exploit/osx/local/sudo_password_bypass S`

Should load fine. If you instead `git checkout upstream/master modules/exploits/osx/local/sudo_password_bypass.rb` right now, you should hit the load error.