Fixed some grammar
Fixed some grammar

Grammar fixes in the environment.rst file

Change-Id: I910da706a1766344bb6645753ab069d34675495a

AlekhyaMallina-Vedams/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals