src: simplify sysv init file handling in make rules
src: simplify sysv init file handling in make rules

Remove lots of duplication in the sysv init file handling, so we can
add more init files without modifying so many places.

Signed-off-by: Daniel P. Berrangé <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

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