add doc for role assignment command

Change-Id: I594d444b6d1ec4e72bed03394178293737f26069
add doc for group command

Change-Id: Iaaa0aeb42f9f940af63863f5d09011b5f7529281
Compute calls ignore region selection

Calls to compute commands ignore region selection.  The region is
not passed to the get_endpoint call.

Change-Id: I1ccfc56d7cb27a00b8982232a40ace21f2c0e9a2
Closes-Bug: 1405416
Merge "add doc for role assignment command"
Merge "Compute calls ignore region selection"