libxlDomainDetachNetDevice: cleanup codes
libxlDomainDetachNetDevice: cleanup codes

Adjust codes to make it cleaner.

Signed-off-by: Chunyan Liu <699809cfcad49bea8cea68d656dfc4a832feaf7a@suse.com>

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