Support language variants on Chinese Wikipedia.

* Chinese Wikipedia Users reporting use of wrong locale.
* This first part updates Accept-Language for Chinese.
* A follow on patch could potentially list two locales:
  -Simplified Chinese (HANS)
  -Traditional Chinese (HANT)
* However, it is probably worth keeping generic Chinese because:
  -HANS/HANT choice may be too generic for user with special dialect.
  -If this patch solves the problem, it's less work for users.
* Another follow on patch should address locales at large:
  -We should first see if this Chinese patch is good enough for ZH.
  -Some languages using Cyrillic alphabet have a similar issue
  -We should solve for same language, different locale LTR/RTL stuff.

Change-Id: I3c4bed32ddfd89916f62cf71ff3996b7a7789815