fix typo in network.rst
fix typo in network.rst

There is a typo for --domain argument in network create:
Owner’s domain (name or ID)",
the last character " should be removed.

Closes-Bug: #1468282
Change-Id: I81d55841e633a52f3913cf5f4a3e6626ebc1f919

dtroyer/python-openstackclient,BjoernT/python-openstackclient,dtroyer/python-openstackclient,BjoernT/python-openstackclient,redhat-openstack/python-openstackclient,redhat-openstack/python-openstackclient,openstack/python-openstackclient,openstack/python-openstackclient