Architecture specific filter missing from Ubuntu builds page

[Scott Kitterman]

Pages like https://launchpad.net/ubuntu/maverick/+builds allow you to select which architecture you want to see results for. The overall page, https://launchpad.net/ubuntu/+builds does not, although urls like https://launchpad.net/ubuntu/+builds?build_text=&build_state=pending&arch_tag=powerpc work perfectly fine. This is just a bit of U/I that was missed when the arch specific options were added.