Partly revert 28b4dd5f for zh and zh-cn/hk/mo/sg/tw messages

For unknown reason (maybe some bug), L10n-bot exported messages in
these languages which had been disabled for translation. Let's remove
them for now and observe whether the bot exports them again.

See I0007fd00579971d4d5bce5e4545492f87ea52867.

Change-Id: I70d384c3a01aff5bbade01917c92e7be9fb936f4
Merge "Partly revert 28b4dd5f for zh and zh-cn/hk/mo/sg/tw messages"