Small edits on help strings
Small edits on help strings

These were initially noted during import into the manuals at
https://review.openstack.org/67502

Fixes include rework of text, missing or extra spaces, wrong
capitalization and no sentence style capitalization.

Change-Id: I56a47de73e0e494a6f770e29dae8065b398ef5af
Co-Authored-By: Diane Fleming <b1ca78774da2a4d33b59cb2e7d4c3ffc12548db9@rackspace.com>

vikt0rs/oslo.db,akash1808/oslo.db,magic0704/oslo.db,openstack/oslo.db,openstack/oslo.db,varunarya10/oslo.db,malor/oslo.db,JioCloud/oslo.db