[patch]: Fix memory leak of symtab.c

[teawater]

Hi Joel,

> Michael told me that you don't have write access.  So I checked you
> patch in for you.  Are there other patches that we approved and didn't
> get checked in?

I don't have other patches need to check-in. Thanks for your help.

>
> As I told Michael, you qualify for write-after-approval priviledges
> (this would allow you to commit the changes yourself after they are
> approved).  Let me know if you're interested.

Great! It's my pleasure. Thanks you very much. :)

Hui