Fix typos in glance/doc/source/configuring.rst
Fix typos in glance/doc/source/configuring.rst

Change-Id: I351e309c10d26cd15a6a7f38b68d93d477d69e93

jumpstarter-io/glance,stevelle/glance,JioCloud/glance,openstack/glance,ozamiatin/glance,openstack/glance,takeshineshiro/glance,JioCloud/glance,ozamiatin/glance,kfwang/Glance-OVA-OVF,scripnichenko/glance,akash1808/glance,jumpstarter-io/glance,stevelle/glance,klmitch/glance,scripnichenko/glance,vuntz/glance,vuntz/glance,saeki-masaki/glance,paramite/glance,kfwang/Glance-OVA-OVF,takeshineshiro/glance,openstack/glance,paramite/glance,dims/glance,klmitch/glance,dims/glance,saeki-masaki/glance,rajalokan/glance,akash1808/glance,rajalokan/glance