Formatting userguide.
Formatting userguide.

Columns formatted for network and volume drivers.
Changes made : Spell errors, table length and indent
Change-Id: Ic8e21868313325b7b0b1cecd45702cf0ecc0e2f9

openstack/magnum,ArchiFleKs/magnum,ArchiFleKs/magnum,openstack/magnum