GLOB_BRACE is already added to MY_GLOB_FLAGS if it is supported on the

platform.  This should resolve some build errors on Solaris.

(issue #13704)
Reported by: dougm


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@154191 65c4cc65-6c06-0410-ace0-fbb531ad65f3