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.

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.

modules/exploits/osx/local/sudo_password_bypass.rb

@@ -5,6 +5,11 @@
 #
 # http://metasploit.com/
 ##
+require 'msf/core'
+require 'rex'
+require 'msf/core/post/common'
+require 'msf/core/post/file'
+require 'msf/core/exploit/exe'
 require 'shellwords'
 
 class Metasploit3 < Msf::Exploit::Local