Fix the freezing ripple on the cr-settings-menu

Fix the freezing ripple on the cr-settings-menu
by disabling the selectedAttribute as a workaround. See
https://github.com/Polymer/polymer/issues/946.

R=michaelpg@chromium.org
BUG=

Committed: https://crrev.com/d67dd33cfa7b9b3a3b716d8bd28735498071621c
Cr-Commit-Position: refs/heads/master@{#321498}

[michaelpg, 2015-03-19 23:47:49]

nice! I'd suggest adding a link to the bug so we know we don't need it when we
upgrade, but lgtm.

[Jeremy Klein, 2015-03-20 00:49:13]

On 2015/03/19 23:47:49, michaelpg wrote:
> nice! I'd suggest adding a link to the bug so we know we don't need it when we
> upgrade, but lgtm.

Done.

[Jeremy Klein, 2015-03-20 00:49:13]

On 2015/03/19 23:47:49, michaelpg wrote:
> nice! I'd suggest adding a link to the bug so we know we don't need it when we
> upgrade, but lgtm.

Done.

[Jeremy Klein, 2015-03-20 00:49:52]

The CQ bit was checked by jlklein@chromium.org

[Jeremy Klein, 2015-03-20 00:49:52]

The patchset sent to the CQ was uploaded after l-g-t-m from
michaelpg@chromium.org
Link to the patchset: https://codereview.chromium.org/1010363003/#ps20001
(title: "Add a todo.")

[commit-bot: I haz the power, 2015-03-20 00:50:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1010363003/20001

[commit-bot: I haz the power, 2015-03-20 02:24:09]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-03-20 02:25:15]

Patchset 2 (id:??) landed as
https://crrev.com/d67dd33cfa7b9b3a3b716d8bd28735498071621c
Cr-Commit-Position: refs/heads/master@{#321498}