MINOR: log: don't check the stream-int's conn_retries if the stream is NULL

Let's simply forget the conn_retries when there is no stream since we
haven't tried to connect yet.
diff --git a/src/log.c b/src/log.c
index 7ac555d..19b448f 100644
--- a/src/log.c
+++ b/src/log.c
@@ -2121,7 +2121,7 @@
 			case LOG_FMT_RETRIES:  // %rq
 				if (s->flags & SF_REDISP)
 					LOGCHAR('+');
-				ret = ltoa_o((s->si[1].conn_retries>0) ?
+				ret = ltoa_o((s && s->si[1].conn_retries > 0) ?
 				                (be->conn_retries - s->si[1].conn_retries) :
 				                be->conn_retries, tmplog, dst + maxsize - tmplog);
 				if (ret == NULL)