virsh: Add option '--no-pkttyagent'

In scripts repeated execution of virsh can result in a lot of
journal noise when pkttyagent gets registered with polkitd each
time.

Closes: https://gitlab.com/libvirt/libvirt/-/issues/757
Signed-off-by: Jens Schmidt <farblos@vodafonemail.de>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>

docs/manpages/virsh.rst

@@ -140,6 +140,14 @@ Output elapsed time information for each command.
 
 
 
+- ``--no-pkttyagent``
+
+Do not register ``pkttyagent`` as authentication agent with the
+polkit system daemon, even if ``virsh`` has been started from a
+terminal.
+
+
+
 - ``-v``, ``--version[=short]``
 
 Ignore all other arguments, and prints the version of the libvirt library