Merged revisions 177624 via svnmerge from

https://origsvn.digium.com/svn/asterisk/trunk

........
  r177624 | jpeeler | 2009-02-19 18:35:53 -0600 (Thu, 19 Feb 2009) | 7 lines
  
  Set sip_request ast_str data to NULL so ast_str_copy allocates space properly
  in copy_request
  
  (issue #14478)
  Reported by: erik_dedecker
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git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.6.1@177626 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -18554,6 +18554,7 @@ static int handle_request_refer(struct sip_pvt *p, struct sip_request *req, int
 					/* Chan2: Call between asterisk and transferee */
 
 	int res = 0;
+	current.req.data = NULL;
 
 	if (req->debug)
 		ast_verbose("Call %s got a SIP call transfer from %s: (REFER)!\n", p->callid, ast_test_flag(&p->flags[0], SIP_OUTGOING) ? "callee" : "caller");