nova-manage vm list fails looking 'instance_type'

The recent set of changes to remove the join on instance_types and get
data from instance_system_metadata missed out the use in
"nova-manage vm list"

fixes bug:  #1158352

Change-Id: I5b06a4fef34331abe40e7429b3abda47070bcbbc
(cherry picked from commit b8f9815c5ab61466009c0447f54abc4c309e4e3f)
Merge "nova-manage vm list fails looking 'instance_type'" into milestone-proposed