As per discussion in PR #427, removed 'with_system_site_packages' suffix in Travis' matrix tests
As per discussion in PR #427, removed 'with_system_site_packages' suffix in Travis' matrix tests

jennolsen84/PyTables,rdhyee/PyTables,joonro/PyTables,PyTables/PyTables,tp199911/PyTables,joonro/PyTables,jennolsen84/PyTables,rabernat/PyTables,gdementen/PyTables,avalentino/PyTables,andreabedini/PyTables,PyTables/PyTables,tp199911/PyTables,mohamed-ali/PyTables,dotsdl/PyTables,FrancescAlted/PyTables,mohamed-ali/PyTables,dotsdl/PyTables,andreabedini/PyTables,gdementen/PyTables,tp199911/PyTables,dotsdl/PyTables,rabernat/PyTables,joonro/PyTables,avalentino/PyTables,jennolsen84/PyTables,mohamed-ali/PyTables,andreabedini/PyTables,andreabedini/PyTables,tp199911/PyTables,PyTables/PyTables,rdhyee/PyTables,rdhyee/PyTables,gdementen/PyTables,jennolsen84/PyTables,mohamed-ali/PyTables,rabernat/PyTables,FrancescAlted/PyTables,rabernat/PyTables,joonro/PyTables,dotsdl/PyTables,avalentino/PyTables,gdementen/PyTables,FrancescAlted/PyTables,rdhyee/PyTables