travis: Fix C++11 requirement for native extensions
travis: Fix C++11 requirement for native extensions

matobet/cockpit-ovirt,mareklibra/cockpit-ovirt,matobet/cockpit-ovirt,mareklibra/cockpit-ovirt,mareklibra/cockpit-ovirt,matobet/cockpit-ovirt,mareklibra/cockpit-ovirt,matobet/cockpit-ovirt