[install] Clarify the paths of the rc files
[install] Clarify the paths of the rc files

Add explicit statement about the rc files' paths
in the installation guide.

Change-Id: Ib652a231ce0c1760630119aa34aa30106d26a20d
Closes-Bug: #1696264

openstack/keystone,mahak/keystone,openstack/keystone,openstack/keystone,mahak/keystone,mahak/keystone