ServiceWorkerServicification: Rename Enabled to Enabled2.

The name is changing due to a change of the server-side configuration.

Bug: 715640
Change-Id: I6804c7178e7d7e3e2d5c34504435f73ca543a77c
Reviewed-on: https://chromium-review.googlesource.com/c/1256397Reviewed-by: Kenichi Ishibashi <bashi@chromium.org>
Reviewed-by: Makoto Shimazu <shimazu@chromium.org>
Reviewed-by: Robert Kaplow (sloooow) <rkaplow@chromium.org>
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596064}

testing/variations/fieldtrial_testing_config.json

@@ -4133,7 +4133,7 @@
             ],
             "experiments": [
                 {
-                    "name": "Enabled",
+                    "name": "Enabled2",
                     "enable_features": [
                         "ServiceWorkerServicification"
                     ]