Make VCR disallow unexpected HTTP requests.

This makes it so that tests fail when they make HTTP requests they
aren't expected to. Update these tests so that they use VCR like they
should.

test/test_helper.rb

@@ -100,5 +100,5 @@ MEMCACHE = MockMemcache.new
 VCR.configure do |c|
   c.cassette_library_dir = "test/fixtures/vcr_cassettes"
   c.hook_into :webmock
-  c.allow_http_connections_when_no_cassette = true
+  # c.allow_http_connections_when_no_cassette = true
 end