Sync latest config file generator from oslo-incubator

The fix to the config file generator to support lazy messages
is the main addition of interest because it is needed after
lazy messages were enabled.

Commits included:
  1a6dfb956 Sanitize FQDN in config generator
  e839886cc Config generator fails with lazy messages
  763eedff6 Fix DictOpt support in config sample generator

Partially implements blueprint i18n-messages
Closes-Bug: #1280826

Change-Id: I2174139ba3767d05924747cbefa377ba8780103d
Merge "Sync latest config file generator from oslo-incubator"