Fix the broken http.test.js by filtering out the _design/main from _all_docs

`_all_docs` view orders all the docs (including `_design/main`) by `id`, **using the ASCII collation**, meaning that `_` comes after the numbers, but before the letters `a-f`. That's why, depending on the UUID-s generated by your CouchDB instance (are they starting with a number, or a letter), `_design/main` will be either in the beginning (the case on my machine), or in the end (probably the case on yours – UUID-s starting with a number), or in the middle (when there are both the UUID-s starting with numbers and letters). Convenient, right? :)

See https://wiki.apache.org/couchdb/View_collation#A_all_docs