replaced depricated 'disable-msg' pylint pragma with 'disable'
locally disable pylint warnings triggered by interface definitions
unit tests: make _makeSUCTest() a local function

The TestGetUnversionedFiles._makeSUCTest() looks like a method but is
used as a local function. Change it to a proper function, to make it
less confusing.

This also fixes 'no-self-argument' pylint warning.
enable no-self-argument and no-method-argument pylint checks