Docs: remove duplicate -u item in create man page
Docs: remove duplicate -u item in create man page

This related to bug:
https://bugzilla.redhat.com/show_bug.cgi?id=916651#c11

Signed-off-by: Wayne Sun <5c40eb6250b2f6a47e210c84de5232afece85d4d@redhat.com>

gczarcinski/libvirt-sandbox,erenyagdiran/libvirt-sandbox,libvirt/libvirt-sandbox,agx/libvirt-sandbox-debian,gczarcinski/libvirt-sandbox,agx/libvirt-sandbox-debian,gczarcinski/libvirt-sandbox,erenyagdiran/libvirt-sandbox,agx/libvirt-sandbox-debian,agx/libvirt-sandbox-debian,agx/libvirt-sandbox-debian,erenyagdiran/libvirt-sandbox,libvirt/libvirt-sandbox,libvirt/libvirt-sandbox,gczarcinski/libvirt-sandbox,gczarcinski/libvirt-sandbox,gczarcinski/libvirt-sandbox,erenyagdiran/libvirt-sandbox