Tests: fixed test of multiple Cache-Control headers.

The $sent_http_cache_control variable will soon use comma as a separator.

http_variables.t

diff --git a/http_variables.t b/http_variables.t
index 4074c6c..e9a73a4 100644
--- a/http_variables.t
+++ b/http_variables.t
@@ -84,7 +84,7 @@
 }
 
 like($log, qr!^/: -$!m, 'no header');
-like($log, qr!^/set: max-age=3600; private; must-revalidate$!m,
+like($log, qr!^/set: max-age=3600[,;] private[,;] must-revalidate$!m,
 	'multi headers');
 
 like($log, qr!^/redefine: no-cache$!m, 'ignoring headers with (hash == 0)');