BUG/MINOR: counters: do not untrack counters before logging

Baptiste Assmann reported a corner case in the releasing of stick-counters:
we release content-aware counters before logging. In the past it was not a
problem, but since now we can log them it, it prevents one from logging
their value. Simply switching the log production and the release of the
counter fixes the issue.

This should be backported into 1.5.
(cherry picked from commit d713bcc326da5d1ac80adab666d7710f3e37650c)
diff --git a/src/proto_http.c b/src/proto_http.c
index 5321f7d..d566bcc 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -4808,7 +4808,6 @@
 
 	s->logs.t_close = tv_ms_elapsed(&s->logs.tv_accept, &now);
 	session_process_counters(s);
-	session_stop_content_counters(s);
 
 	if (s->txn.status) {
 		int n;
@@ -4842,6 +4841,8 @@
 		s->do_log(s);
 	}
 
+	/* stop tracking content-based counters */
+	session_stop_content_counters(s);
 	session_update_time_stats(s);
 
 	s->logs.accept_date = date; /* user-visible date for logging */