BUG/MINOR: conf: calloc untested

A calloc is executed without check of its returns code.
diff --git a/src/cfgparse.c b/src/cfgparse.c
index a355aa9..40fd7da 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -4012,6 +4012,10 @@
 		}
 
 		rule = calloc(1, sizeof(*rule));
+		if (!rule) {
+			Alert("Out of memory error.\n");
+			goto out;
+		}
 		rule->cond = cond;
 		rule->be.name = strdup(args[1]);
 		LIST_INIT(&rule->list);