Split --syntax-check and --list-tasks steps in test-bifrost.sh
Split --syntax-check and --list-tasks steps in test-bifrost.sh

ansible-playbook's --syntax-check and --list-tasks can't be used
together because --syntax-check makes ansible-playbook to exit right
after it checks the playbook file so the list of tasks is never
reported. For example:

[...]
+ /opt/stack/ansible/bin/ansible-playbook -vvvv -i inventory/localhost
test-bifrost-create-vm.yaml --syntax-check --list-tasks
No config file found; using defaults
1 plays in test-bifrost-create-vm.yaml

playbook: test-bifrost-create-vm.yaml
+ /opt/stack/ansible/bin/ansible-playbook -vvvv -i inventory/localhost
test-bifrost.yaml --syntax-check --list-tasks -e testing_user=cirros
No config file found; using defaults
9 plays in test-bifrost.yaml

playbook: test-bifrost.yaml
[...]

As a result of which, split these two steps in order for
both operations to be executed as expected.

Change-Id: I053dbb72c95ddb7bb3ba5063317c03dc31d98e31
Signed-off-by: Markos Chandras <33d8b43ece1558bd62b361ce5e954c5d9a97a7a2@suse.de>

openstack/bifrost,openstack/bifrost