tests: qemuxml2xml: Clean up disk-mirror
tests: qemuxml2xml: Clean up disk-mirror

Instead of testing it twice using WHEN_ACTIVE and WHEN_INACTIVE
separately, just use WHEN_BOTH.

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