BUG #13471: Reload with include_dir results in incorrect "contains errors" message

The following bug has been logged on the website:

Bug reference:      13471
Logged by:          Andomar
Email address:      andomar@aule.net
PostgreSQL version: 9.4.4
Operating system:   CentOS 6.5
Description:


Steps to reproduce problem:
1. Create a new Postgres installation with "pg_ctl init"
2. In postgresql.conf, remove the comment before "include_dir = 'conf.d'"
3. Create a file "conf.d/extra.conf" containing "max_connections = 123"
4. Start Postgres with "pg_ctl start"
5. Reload Postgres with "pg_ctl reload"
6. Read the log file in pg_log; it says:
  received SIGHUP, reloading configuration files
  parameter "max_connections" cannot be changed without restarting the
server
  configuration file "/home/wessel/test/postgresql.conf" contains errors;
unaffected changes were applied

But max_connections was not changed after restarting the server. These
messages are incorrect.