Revert "Verify soruce setup code."

This reverts commit b894c72.

Author: mostlyobvious

lib/nanoc/github.rb

@@ -1,6 +1,6 @@
 require "nanoc"
 require "octokit"
-require "faraday/http_cache"
+
 
 module Nanoc
   module Github

test/source_test.rb

@@ -121,10 +121,6 @@ def test_use_access_token
           .to_return(status: 404)
         source_with_token.items
       end
-
-      def test_up
-        assert source_with_posts.up
-      end
     end
   end
 end