small changes to module003-ch007-swift-cluster-architecture

added that - more capacity in the access layer that will
added “a” between words
changed to Object Storage
10-gigabit network hyphen added

Change-Id: Ie3ed5c5746c2cffe9a85a8f00ab0f82728a98e9e
Merge "small changes to module003-ch007-swift-cluster-architecture"