gc.c: revert return

* gc.c (get_envparam_size): revert `return` statement removed by
  accident.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44873 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

gc.c

@@ -5667,6 +5667,7 @@ get_envparam_size(const char *name, size_t *default_value, size_t lower_bound)
 		fprintf(stderr, "%s=%"PRIdSIZE" (default value: %"PRIdSIZE")\n", name, val, *default_value);
 	    }
 	    *default_value = (size_t)val;
+	    return 1;
 	}
 	else {
 	    if (RTEST(ruby_verbose)) {