BUG/MINOR: haterm: missing allocation check in copy_argv()

This is a very minor bug with a very low probability of occurring.
However, it could be flagged by a static analyzer or result in a small
contribution, which is always time-consuming for very little gain.

src/haterm_init.c

@@ -474,6 +474,9 @@ void haproxy_init_args(int argc, char **argv)
 char **copy_argv(int argc, char **argv)
 {
 	char **ret = calloc(1, sizeof(*ret));
-	*ret = strdup("");
+
+	if (*ret)
+		*ret = strdup("");
+
 	return ret;
 }