Allow 'replaced' changed managed files in schema

  Fixes Github Issue#157
Allow 'replaced' files in config file schema
Add unit test to check for error on invalid enum in schema
Add test to check for 'replaced' changed-managed-files

  Adding a test to make sure Issue#157 is fixed.
Merge pull request #158 from SUSE/fix_157

Allow 'replaced' changed managed files in schema