Add a way for config files to match specific distros

The persona and origins file and distro file can now
have special keys that like 'red-hat-enterprise-linux-server-7.0'
or 'red-hat-enterprise-linux-server-6.5' that can specify additional
'dependency_handler' data that will be merged into the distros
initial 'dependency_handler' data (from the initial yaml file).

Change-Id: Ib52bbdc4be44e9af3a6c741e327bd2f810c1c723
Merge "Add a way for config files to match specific distros"