CXMAN-261: Add Credentials to pylint.rc/ignored-classes
CXMAN-261: Add Credentials to pylint.rc/ignored-classes

The Credentials class is dynamically populated, so we get a lot of
pylint warnings about it. Ignore them.

SLS-Dev/cxmanage,SLS-Dev/cxmanage,SilverLiningSystems/cxmanage-test2,SilverLiningSystems/cxmanage-test,SilverLiningSystems/cxmanage-test,Cynerva/cxmanage,SilverLiningSystems/cxmanage-test2,Cynerva/cxmanage