More Global EC doc updates
More Global EC doc updates

Soften the language about inefficiency on read and strengthen the
language encouraging the use of read affinity and composite rings.

Change-Id: Idc81a8c71e74ae28d384759700c5268d77ae3c85

matthewoliver/swift,psachin/swift,redbo/swift,notmyname/swift,matthewoliver/swift,swiftstack/swift,nadeemsyed/swift,tipabu/swift,openstack/swift,swiftstack/swift,nadeemsyed/swift,openstack/swift,nadeemsyed/swift,notmyname/swift,smerritt/swift,clayg/swift,smerritt/swift,matthewoliver/swift,tipabu/swift,openstack/swift,clayg/swift,smerritt/swift,tipabu/swift,nadeemsyed/swift,smerritt/swift,matthewoliver/swift,psachin/swift,swiftstack/swift,clayg/swift,redbo/swift,psachin/swift,openstack/swift,notmyname/swift,notmyname/swift,tipabu/swift,clayg/swift,psachin/swift