BUG/MINOR: ssl: OCSP minimum update threshold not properly set

An arbitrary 5 minutes minimum interval between two updates of the same
OCSP response is defined but it was not properly used when inserting
entries in the update tree.

This patch does not need to be backported.

src/ssl_ocsp.c

@@ -869,7 +869,8 @@ int ssl_ocsp_update_insert(struct certificate_ocsp *ocsp)
 	 * updated more than once every 5 minutes in order to avoid continuous
 	 * update of the same response. */
 	if (b_data(&ocsp->response))
-		ocsp->next_update.key = MAX(ocsp->next_update.key, SSL_OCSP_UPDATE_DELAY_MIN);
+		ocsp->next_update.key = MAX(ocsp->next_update.key,
+                                            now.tv_sec + SSL_OCSP_UPDATE_DELAY_MIN);
 
 	HA_SPIN_LOCK(OCSP_LOCK, &ocsp_tree_lock);
 	eb64_insert(&ocsp_update_tree, &ocsp->next_update);