[Android]Use zh instead of zh-rTW as output folder of zh_TW translation

chrome/android/java/strings/android_chrome_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
 <!-- android_chrome_strings.grd contains strings for Chrome for Android.
 
 FAQ:
   - How do I add, change, or remove a string?
       Just update this file.
   - Translations will happen automatically??
       Yes, indeed. Just add your string before the branch point and
       make the description good.
@@ skipping 57 matching lines @@
     <output filename="values-sk/android_chrome_strings.xml" lang="sk" type="android" />
     <output filename="values-sl/android_chrome_strings.xml" lang="sl" type="android" />
     <output filename="values-sr/android_chrome_strings.xml" lang="sr" type="android" />
     <output filename="values-sv/android_chrome_strings.xml" lang="sv" type="android" />
     <output filename="values-sw/android_chrome_strings.xml" lang="sw" type="android" />
     <output filename="values-th/android_chrome_strings.xml" lang="th" type="android" />
     <output filename="values-tr/android_chrome_strings.xml" lang="tr" type="android" />
     <output filename="values-uk/android_chrome_strings.xml" lang="uk" type="android" />
     <output filename="values-vi/android_chrome_strings.xml" lang="vi" type="android" />
     <output filename="values-zh-rCN/android_chrome_strings.xml" lang="zh-CN" type="android" />
-    <output filename="values-zh-rTW/android_chrome_strings.xml" lang="zh-TW" type="android" />
+    <!-- Use zh instead of zh-rTW so that Android will let zh-HK fall back to zh-TW.-->

[grt (UTC plus 2), 2016/04/30 11:09:32]

nit: add space after sentence before "-->"

+    <output filename="values-zh/android_chrome_strings.xml" lang="zh-TW" type="android" />
   </outputs>
   <translations>
     <file lang="am" path="translations/android_chrome_strings_am.xtb" />
     <file lang="ar" path="translations/android_chrome_strings_ar.xtb" />
     <file lang="bg" path="translations/android_chrome_strings_bg.xtb" />
     <file lang="ca" path="translations/android_chrome_strings_ca.xtb" />
     <file lang="cs" path="translations/android_chrome_strings_cs.xtb" />
     <file lang="da" path="translations/android_chrome_strings_da.xtb" />
     <file lang="de" path="translations/android_chrome_strings_de.xtb" />
     <file lang="el" path="translations/android_chrome_strings_el.xtb" />
@@ skipping 2273 matching lines @@
       <!-- Migration strings -->
       <message name="IDS_TAB_SWITCHER_CALLOUT_HEADER" desc="Header for the Tab Switcher callout.">
         Quickly switch tabs
       </message>
       <message name="IDS_TAB_SWITCHER_CALLOUT_BODY" desc="Indicates that clicking the tab switcher button gives you quick access to your tabs.">
         Tap this button for quick access to your tabs.
       </message>
     </messages>
   </release>
 </grit>