configure: Remove nested conditionals in LIBVIRT_CHECK_INIT_SCRIPT
configure: Remove nested conditionals in LIBVIRT_CHECK_INIT_SCRIPT

We don't need them any longer; moreover, the previous structure
made it very easy for bugs to slip in, by having the result of one
check influence the following one.

By placing the check for "$with_init_script" = check front and
center, hopefully this won't happen (as easily) again.

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