Fixed escaping for grep, added -L to curl to avoid 301 and follow path to new file location.

Test Plan:
. Manually ran a sh script that searched for -Qunused-arguments to test the sh behavior. Also, no longer receiving error notice.
. curl of install wasn't working without -L, adding it fixed things.

Reviewers: marcos, csilvers

Reviewed By: csilvers

Differential Revision: http://phabricator.khanacademy.org/D11302