Fix a crash when saying certain numbers in Chinese

Fix a crash when saying certain numbers in Chinese

This commit fixes a crash that was occurring when attempting to
say a number between 10000 and 100000 due to dividing by 0.

This also removes some places where a "zero" is spoken when it
should not be.

(closes issue #14291)
Reported by: dant
Patches:
      say.c-14291.diff uploaded by dant (license 670)
Tested by: dant

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@169794 65c4cc65-6c06-0410-ace0-fbb531ad65f3