LXC: check whether we get MemSwap[Total|Usage]
LXC: check whether we get MemSwap[Total|Usage]

Signed-off-by: Chen Hanxiao <818f8a165c25fa146ecad28e2ef3e3fb996fa364@cn.fujitsu.com>

agx/libvirt,datto/libvirt,libvirt/libvirt,agx/libvirt,agx/libvirt,agx/libvirt,rlaager/libvirt,rlaager/libvirt,shugaoye/libvirt,andreabolognani/libvirt,shugaoye/libvirt,rlaager/libvirt,nertpinx/libvirt,olafhering/libvirt,nertpinx/libvirt,elmarco/libvirt,zippy2/libvirt,datto/libvirt,jfehlig/libvirt,nertpinx/libvirt,taget/libvirt,nertpinx/libvirt,taget/libvirt,eskultety/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,zippy2/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,libvirt/libvirt,jfehlig/libvirt,shugaoye/libvirt,VenkatDatta/libvirt,VenkatDatta/libvirt,olafhering/libvirt,andreabolognani/libvirt,jfehlig/libvirt,jardasgit/libvirt,rlaager/libvirt,jardasgit/libvirt,taget/libvirt,olafhering/libvirt,VenkatDatta/libvirt,VenkatDatta/libvirt,nertpinx/libvirt,libvirt/libvirt,zippy2/libvirt,jardasgit/libvirt,datto/libvirt,zippy2/libvirt,eskultety/libvirt,datto/libvirt,eskultety/libvirt,shugaoye/libvirt,libvirt/libvirt,crobinso/libvirt,olafhering/libvirt,andreabolognani/libvirt,datto/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,agx/libvirt,taget/libvirt,VenkatDatta/libvirt,jfehlig/libvirt,crobinso/libvirt,eskultety/libvirt,elmarco/libvirt,fabianfreyer/libvirt,elmarco/libvirt,jardasgit/libvirt,elmarco/libvirt,rlaager/libvirt,shugaoye/libvirt,taget/libvirt,crobinso/libvirt,elmarco/libvirt,crobinso/libvirt,eskultety/libvirt,fabianfreyer/libvirt