internal: Fix caching issues with config variants. Before, changing config variant values could incorrectly re-use a previously cached config as long as there were the same number of variants. Now we build a stricter cache hash based on the actual values.

---
admin: true
url: /
in:
    pages/one.html: ''
    posts/2016-01-01_post1.html: ''
out_contains: |
    1 pages