Revert "Use hash symbols instead of strings for keys"

Summary:
Fix a regression where project properties aren't accessible anymore,
and so build URLs aren't included on the dashboard.

This reverts commit 517786ca4886.

Ref T1449

Test Plan:

$ bundle exec rackup -o 0.0.0.0 -p 4567
$ curl localhost:4567 | grep ci

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1449

Differential Revision: https://devcentral.nasqueron.org/D1801