An introduction with some basic concepts and explanations around OCIO config and synColor config files has been added to the MtoA (2017) user guide in the links below.
https://support.solidangle.com/display/A5AFMUG/Maya+2017
https://support.solidangle.com/display/A5AFMUG/Output
As this is a frequently asked question we have provided both the question and answer in this thread.
Lee Griggs
Arnold rendering specialist
AUTODESK