Update swarm test request to store the manifest in the request parameter, instead of just passing the json data directly.
Update swarm test request to store the manifest in the request parameter, instead of just passing the json data directly.

TBR=maruel@chromium.org
BUG=


Review URL: https://chromiumcodereview.appspot.com/11826057

git-svn-id: d5a9b8648c52d490875de6588c8ee7ca688f9ed1@176095 0039d316-1c4b-4281-b951-d872f2087c98

luci/luci-py,luci/luci-py,luci/luci-py,luci/luci-py