lxc: rename vmdef to persistentDef
lxc: rename vmdef to persistentDef

A few functions using virDomainLiveConfigHelperMethod use the generic
name 'vmdef' to point to the persistent definition.

Use persistentDef and/or persistentDefCopy to make its purpose obvious.

crobinso/libvirt,crobinso/libvirt,libvirt/libvirt,jfehlig/libvirt,eskultety/libvirt,datto/libvirt,andreabolognani/libvirt,zippy2/libvirt,jardasgit/libvirt,olafhering/libvirt,VenkatDatta/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,datto/libvirt,crobinso/libvirt,taget/libvirt,eskultety/libvirt,libvirt/libvirt,jfehlig/libvirt,VenkatDatta/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,jfehlig/libvirt,nertpinx/libvirt,eskultety/libvirt,nertpinx/libvirt,VenkatDatta/libvirt,eskultety/libvirt,nertpinx/libvirt,jardasgit/libvirt,datto/libvirt,eskultety/libvirt,jardasgit/libvirt,libvirt/libvirt,jardasgit/libvirt,zippy2/libvirt,fabianfreyer/libvirt,datto/libvirt,libvirt/libvirt,nertpinx/libvirt,datto/libvirt,taget/libvirt,taget/libvirt,olafhering/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,taget/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt,jfehlig/libvirt,VenkatDatta/libvirt,andreabolognani/libvirt,zippy2/libvirt,crobinso/libvirt,olafhering/libvirt,taget/libvirt,zippy2/libvirt,olafhering/libvirt,nertpinx/libvirt,jardasgit/libvirt