tools: Update the help description of the adapter-parent field
tools: Update the help description of the adapter-parent field

One short sentence won't do it justice, but it could help by listing
scsi_hostN and vHBA to point one in the right direction.

Signed-off-by: John Ferlan <87558058f6f829e5ec976c8ef960720af4ff9c7d@redhat.com>

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