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 <mchandras@suse.de>

scripts/test-bifrost.sh

@@ -89,17 +89,17 @@ fi
 cd $BIFROST_HOME/playbooks
 
 # Syntax check of dynamic inventory test path
-${ANSIBLE} -vvvv \
-       -i inventory/localhost \
-       test-bifrost-create-vm.yaml \
-       --syntax-check \
-       --list-tasks
-${ANSIBLE} -vvvv \
-       -i inventory/localhost \
-       ${TEST_PLAYBOOK} \
-       --syntax-check \
-       --list-tasks \
-       -e testing_user=${TESTING_USER}
+for task in syntax-check list-tasks; do
+    ${ANSIBLE} -vvvv \
+           -i inventory/localhost \
+           test-bifrost-create-vm.yaml \
+           --${task}
+    ${ANSIBLE} -vvvv \
+           -i inventory/localhost \
+           ${TEST_PLAYBOOK} \
+           --${task} \
+           -e testing_user=${TESTING_USER}
+done
 
 # Create the test VM
 ${ANSIBLE} -vvvv \