Fix typos in configuring.rst
Fix typos in configuring.rst

Fix several typos.

Change-Id: Id6f610974f4b68e4786b0241478c5b7b7c622eac

klmitch/glance,klmitch/glance,openstack/glance,stevelle/glance,dims/glance,openstack/glance,rajalokan/glance,rajalokan/glance,dims/glance,openstack/glance,stevelle/glance