(Cleanup) MD Settings: explicitly import util in people-page

Currently people-page uses listenOnce() from util.js, which it only got access to transitively from other deps and is fragile.

BUG=None
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2807513002
Cr-Commit-Position: refs/heads/master@{#462702}

chrome/browser/resources/settings/people_page/compiled_resources2.gyp

@@ -122,6 +122,7 @@
         '<(DEPTH)/ui/webui/resources/js/compiled_resources2.gyp:i18n_behavior',
         '<(DEPTH)/ui/webui/resources/js/compiled_resources2.gyp:icon',
         '<(DEPTH)/ui/webui/resources/js/compiled_resources2.gyp:load_time_data',
+        '<(DEPTH)/ui/webui/resources/js/compiled_resources2.gyp:util',
         '<(DEPTH)/ui/webui/resources/js/compiled_resources2.gyp:web_ui_listener_behavior',
         'easy_unlock_browser_proxy',
         'easy_unlock_turn_off_dialog',

chrome/browser/resources/settings/people_page/people_page.html

@@ -4,6 +4,7 @@
 <link rel="import" href="chrome://resources/html/i18n_behavior.html">
 <link rel="import" href="chrome://resources/html/icon.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
+<link rel="import" href="chrome://resources/html/util.html">
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-collapse/iron-collapse.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/neon-animation/neon-animatable.html">