After the deletion of page_cycler.morejs benchmark, these are the only two
gclient configs we need across chromium.perf, chromium.perf.fyi, and
tryserver.chromium.perf. Rename from "perf" to "chromium_perf" to match chromium
config. This CL will be followed up with one to delete "perf".


BUG=611484

Review-Url: https://codereview.chromium.org/1976843002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@300600 0039d316-1c4b-4281-b951-d872f2087c98