Add check for t38_terminal_init in spandsp (not found in 0.0.6, so it should fail reasonably)

(closes issue #13473)
 Reported by: genie
 Patches: 
       20080916__bug13473.diff.txt uploaded by Corydon76 (license 14)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@157784 65c4cc65-6c06-0410-ace0-fbb531ad65f3