message: Fix tests and centos 6.9 httpd startup
  unexpectedly broke some tests.
  This resolves the test errors, but also allows httpd to startup on the CentOS 6.9
  GCE VM.
diff: @@ -526,7 +526,7 @@ ModPagespeedCompressMetadataCache true
  # different depending on whether we are running system tests as root
  # or as a normal user. Note that fetches must be done with
  # http_proxy=SECONDARY_HOST:SECONDARY_PORT.
  -Listen 127.0.0.1:@@APACHE_SECONDARY_PORT@@
  +Listen *:@@APACHE_SECONDARY_PORT@@
  NameVirtualHost localhost:@@APACHE_SECONDARY_PORT@@
  <VirtualHost localhost:@@APACHE_SECONDARY_PORT@@>
  ServerName secondary.example.com
  