Added directory creation to setup.sh for /var/log/inboxapp and /var/lib/inboxapp

Summary:

Test Plan: Test with fresh install, confirm that ./inbox works on the first try now

Reviewers: mg

CC:
Added directory creation to setup.sh for /var/log/inboxapp and /var/lib/inboxapp

Test Plan: Test with fresh install, confirm that ./inbox works on the first try now

Reviewers: mg

Reviewed By: mg

Differential Revision: https://review.inboxapp.com/D110