Improve help text of flavors config options
Improve help text of flavors config options

1. Added more verbose to flavor configuration options
2. Fixed syntax for consistency

Implements blueprint centralize-config-options-newton

Change-Id: I55e45ad9e8dc0455811b28e8aaf600b1fb026f3f

mahak/nova,hanlind/nova,vmturbo/nova,mahak/nova,sebrandon1/nova,rajalokan/nova,rahulunair/nova,hanlind/nova,phenoxim/nova,openstack/nova,sebrandon1/nova,jianghuaw/nova,openstack/nova,jianghuaw/nova,klmitch/nova,gooddata/openstack-nova,phenoxim/nova,Juniper/nova,jianghuaw/nova,jianghuaw/nova,rahulunair/nova,Juniper/nova,rajalokan/nova,Juniper/nova,gooddata/openstack-nova,gooddata/openstack-nova,hanlind/nova,mikalstill/nova,sebrandon1/nova,klmitch/nova,cloudbase/nova,alaski/nova,cloudbase/nova,Juniper/nova,cloudbase/nova,rajalokan/nova,vmturbo/nova,klmitch/nova,mikalstill/nova,rajalokan/nova,vmturbo/nova,rahulunair/nova,mikalstill/nova,mahak/nova,gooddata/openstack-nova,klmitch/nova,vmturbo/nova,openstack/nova,alaski/nova