MD Settings: change "Yay!" to "Cheers." because Alan said so

R=dschuyler@chromium.org
BUG=651720

Review-Url: https://codereview.chromium.org/2391803003
Cr-Commit-Position: refs/heads/master@{#422873}

chrome/app/settings_chromium_strings.grdp

@@ -36,7 +36,7 @@
   <!-- Default Browser Page -->
   <if expr="not chromeos">
     <message name="IDS_SETTINGS_DEFAULT_BROWSER_DEFAULT" desc="The text displayed when Chrome is not the default browser">
-      Chromium is your default browser. Yay!
+      Chromium is your default browser. Cheers.
     </message>
     <message name="IDS_SETTINGS_DEFAULT_BROWSER_MAKE_DEFAULT" desc="Default browser checkbox label">
       Make Chromium the default browser

chrome/app/settings_google_chrome_strings.grdp

@@ -36,7 +36,7 @@
   <!-- Default Browser Page -->
   <if expr="not chromeos">
     <message name="IDS_SETTINGS_DEFAULT_BROWSER_DEFAULT" desc="The text displayed when Chrome is not the default browser">
-      Google Chrome is your default browser. Yay!
+      Google Chrome is your default browser. Cheers.
     </message>
     <message name="IDS_SETTINGS_DEFAULT_BROWSER_MAKE_DEFAULT" desc="Default browser checkbox label">
       Make Google Chrome the default browser