Update paper-radio-button to 0.5.4.

Update paper-radio-button to 0.5.4.

The latest <paper-radio-button> matches the Material Design spec. The
MD-Settings page will make use of the cr-checkbox which wraps a paper-checkbox which extends paper-radio-button.

Since paper-radio-button isn't currently used in Chromium there shouldn't
be any side effects for this change.

BUG=457513
Committed: https://crrev.com/53e8439a5807f3ffd3e3f5d4dbd3f1d1614ef249
Cr-Commit-Position: refs/heads/master@{#316638}

[Oren Blasberg, 2015-02-12 20:10:27]

orenb@chromium.org changed reviewers:
+ michaelpg@chromium.org

[Oren Blasberg, 2015-02-17 18:24:20]

friendly ping

[michaelpg, 2015-02-17 18:53:30]

lgtm

[Oren Blasberg, 2015-02-17 18:55:45]

The CQ bit was checked by orenb@chromium.org

[commit-bot: I haz the power, 2015-02-17 18:56:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/924623002/1

[commit-bot: I haz the power, 2015-02-17 20:04:29]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-17 20:05:20]

Patchset 1 (id:??) landed as
https://crrev.com/53e8439a5807f3ffd3e3f5d4dbd3f1d1614ef249
Cr-Commit-Position: refs/heads/master@{#316638}