Break up update translations into two scripts.

Summary:
The first script will do all the work.  Then jenkins will call make
build - preparing a new genfiles dir for deploy job.  Then we call the
second script which will check in the file.

Test Plan: cross-fingers, update jenkins job to use the two scripts, then run it.

Reviewers: csilvers

Reviewed By: csilvers

Differential Revision: http://phabricator.khanacademy.org/D11839