Fabric: Simplify get_firmware_info_dict and get_versions_dict
Fabric: Simplify get_firmware_info_dict and get_versions_dict

Instead of building up the dictionaries ourselves, let's use the
Node method that already does that for us.

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