note: trim on hostname for autoscale instances (#575)

* note: trim on hostname for autoscale instances

Related https://github.com/apache/cloudstack/pull/11327

Signed-off-by: Abhishek Kumar <abhishek.mrt22@gmail.com>

* Update source/adminguide/autoscale_with_virtual_router.rst

Co-authored-by: Wei Zhou <weizhou@apache.org>

* Update source/adminguide/autoscale_with_virtual_router.rst

Co-authored-by: Wei Zhou <weizhou@apache.org>

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Signed-off-by: Abhishek Kumar <abhishek.mrt22@gmail.com>
Co-authored-by: Wei Zhou <weizhou@apache.org>