Use correct format to convert QCOW2 image

When converting a QCOW2 image to VMDK format the QCOW2 input format must
be specified, not RAW.

Change-Id: Ib8a7084ebaf24e94dc3a9b132a22ab8d355bb562
Closes-Bug: #1282105
Fixes typos and updates Keystone concepts image

This patch fixes a number of typos and generally cleans
up the keystone concepts image in the install-guide.

Change-Id: I437600288e3ab181668b55493451a0b4ef5dd314
Closes-Bug: #1281775
Merge "Use correct format to convert QCOW2 image"
Merge "Fixes typos and updates Keystone concepts image"