Setting tag sfa-2.1-2

Setting tag sfa-2.1-2
registry database has user's keys and mail (known as v0 for migrate)
pl importer properly maintains user's keys and mail
pl driver now to handle 'role' when adding person record (exp.)
first draft of federica driver with config section
SFA_GENERIC_FLAVOUR in usual variables for sfa-config-tty
plus, from master as of tag merged-in-sfa-2.1-2:
disk_image revisited
new nova_shell nova_driver & various tweaks for openstack