adds support for t38 pass through patch brought up to trunk from

bug 5090 by josh colp.  Thanks to everyone who help get this patch through
especially to the author Steven Underwood.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@33890 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channel.c

@@ -2383,6 +2383,10 @@ int ast_write(struct ast_channel *chan, struct ast_frame *fr)
 		res = (chan->tech->write_video == NULL) ? 0 :
 			chan->tech->write_video(chan, fr);
 		break;
+	case AST_FRAME_MODEM:
+		res = (chan->tech->write == NULL) ? 0 :
+			chan->tech->write(chan, fr);
+		break;
 	case AST_FRAME_VOICE:
 		if (chan->tech->write == NULL)
 			break;	/*! \todo XXX should return 0 maybe ? */