docs: Remove avocado-virt from MaintenanceGuide

The avocado-virt and avocado-virt-tests are not packaged anymore and
should only be installed from source.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

docs/source/MaintenanceGuide.rst

@@ -75,11 +75,6 @@ content in the following repositories:
 
 * ``avocado``
 * ``avocado-vt``
-* ``avocado-virt``
-* ``avocado-virt-tests``
-
-In this order of importance. Some times ``avocado-virt`` and ``avocado-virt-tests``
-might not get updates, so it's OK to skip them.
 
 Tag all repositories
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