py: Query.__add__()
py: Query.__add__()

saves us q.run() when concatenating with a package list.

Conan-Kudo/libhif,Conan-Kudo/libhif,edynox/libdnf,cgwalters/libhif,hughsie/libhif,rpm-software-management/libdnf,cgwalters/libhif,rpm-software-management/libdnf,hughsie/libhif,edynox/libdnf,rpm-software-management/libhif,rpm-software-management/libdnf,rpm-software-management/libhif,Conan-Kudo/libhif,Conan-Kudo/libhif,edynox/libdnf,cgwalters/libhif,edynox/libdnf,rpm-software-management/libdnf,hughsie/libhif,rpm-software-management/libhif,hughsie/libhif,cgwalters/libhif,rpm-software-management/libhif