potentially uninitialized variable.

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@4243 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/mod/endpoints/mod_sofia/mod_sofia.c

@@ -969,7 +969,7 @@ static void do_invite(switch_core_session_t *session)
 	switch_stream_handle_t stream = {0};
 	switch_hash_index_t *hi;
 	void *vval;
-	char *extra_headers;
+	char *extra_headers = NULL;
 	const void *vvar;
 
     channel = switch_core_session_get_channel(session);