Update vHello_3Node_Tacker test for Danube

Update vHello_3Node_Tacker test for Danube

JIRA: MODELS-23

blueprint.yaml:
Add vHello key injection into blueprint for debug.
Fix URL for favicon.
Fix docker install pre-reqs.

vHello_3Node_Tacker.sh:
Fix tests in say_hello.
Correct path to blueprint in copy_blueprint.
Create and inject nova keypair.
Use actual $FLOATING_NETWORK_NAME in floating ip allocation.
Fix use of array variables vdu_ip/id/etc.

Change-Id: Id4a04ecf86d3715d11c65298c22c586e20f78d4c
Signed-off-by: bryan <bryan.sullivan@att.com>