MINOR: tree-wide: use free_acl_cond() where relevant

Now that we have free_acl_cond(cond) function that does cond prune then
frees cond, replace all occurences of this pattern:

   | prune_acl_cond(cond)
   | free(cond)

with:

   | free_acl_cond(cond)
diff --git a/src/http_rules.c b/src/http_rules.c
index 1efba4a..192f0c7 100644
--- a/src/http_rules.c
+++ b/src/http_rules.c
@@ -322,10 +322,7 @@
 {
 	struct logformat_node *lf, *lfb;
 
-	if (rdr->cond) {
-		prune_acl_cond(rdr->cond);
-		free(rdr->cond);
-	}
+	free_acl_cond(rdr->cond);
 	free(rdr->rdr_str);
 	free(rdr->cookie_str);
 	list_for_each_entry_safe(lf, lfb, &rdr->rdr_fmt, list) {
@@ -519,8 +516,7 @@
 		http_free_redirect_rule(rule);
 	else if (cond) {
 		/* rule not yet allocated, but cond already is */
-		prune_acl_cond(cond);
-		free(cond);
+		free_acl_cond(cond);
 	}
 
 	return NULL;