init last_rseq with 0

- fixes a bug causing to re-transmit a provisional reply for ever if no PRACK is used.

core/sip/sip_trans.cpp

@@ -54,7 +54,8 @@ inline timer** fetch_timer(unsigned int timer_type, timer** base)
 sip_trans::sip_trans()
     : msg(0),
       retr_buf(0),
-      retr_len(0)
+      retr_len(0),
+      last_rseq(0)
 {
     memset(timers,0,SIP_TRANS_TIMERS*sizeof(void*));
 }

core/sip/sip_trans.h

@@ -143,7 +143,7 @@ class sip_trans
     int   retr_len;
 
     /** used by UAS only; keeps RSeq of last sent reliable 1xx */
-    unsigned last_rseq;
+    unsigned int last_rseq;
 
     /** Destination for retransmissions */
     sockaddr_storage retr_addr;