spec: remove python-argparse dependency on fc26
spec: remove python-argparse dependency on fc26

Fedora 26 doesn't provide the python-argparse
package anymore: the argparse module is provided by the
base python-libs package.

Fix the spec file to declare the correct dependency.

Bug-Url: https://bugzilla.redhat.com/1494594
Change-Id: Iee0c1afd610e9cfcf82196f6882321a87e0b48cb

oVirt/ovirt-vmconsole,oVirt/ovirt-vmconsole,oVirt/ovirt-vmconsole