session: skip timestamp init for non-blocking case

Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

src/session.c

@@ -599,7 +599,11 @@ int ssh_handle_packets_termination(ssh_session session,
         }
     }
 
+    /* avoid unnecessary syscall for the SSH_TIMEOUT_NONBLOCKING case */
+    if (timeout != SSH_TIMEOUT_NONBLOCKING) {
         ssh_timestamp_init(&ts);
+    }
+
     tm = timeout;
     while(!fct(user)) {
         ret = ssh_handle_packets(session, tm);