[devel] Update SiteDirector._getPilotOptions signature for https://github.com/DIRACGrid/DIRAC/pull/4925

The Python 3 pylint check in !905 (merged) is failing because it's using the integration branch of DIRAC while the Python 2 pylint check uses the release that was used for an LHCbDIRAC tag. This change comes from https://github.com/DIRACGrid/DIRAC/pull/4925

It's not clear how to make Python 3 behave like Python 2 for the CI as Python 3 doesn't know what the current version is before being installed. Regardless this will be a bug as soon as DIRAC is updated in the releases.cfg so this is the fix.