old_contents: 
  // activate a version of a package
  // this presumes that it's been installed
  // no need to worry about dependencies, because they were
  // installed into the child package anyhow.
  
  var mkdir = require("./utils/mkdir-p"),
    processCb = require("./utils/process-cb");
  
  module.exports = activate;
  
  function activate (pkg, version, cb) {
    
  }
  
new_contents: 
  // activate a version of a package
  // this presumes that it's been installed
  // no need to worry about dependencies, because they were
  // installed into the child package anyhow.
  
  var mkdir = require("./utils/mkdir-p"),
    exec = require("./utils/exec");
  
  module.exports = activate;
  
  function activate (pkg, version, cb) {
    
  }
  
subject: Rename process-cb to exec