[contrail 3.0]Some OSTF tests failed after Contrail db role deletion

Scenario:
            1. Create an environment with "Neutron with tunneling
               segmentation" as a network configuration
            2. Enable and configure Contrail plugin
            3. Add some controller, compute nodes
            4. Add 1 node with "contrail-control", "contrail-config" and
               "contrail-db" roles
            5. Deploy cluster
            6. Check Controller and Contrail nodes status
            7. Add one node with "contrail-db" role
            8. Deploy changes
            9. Run OSTF tests
            10. Delete node with "contrail-db", which was added before
            11. Deploy changes
            12. Run OSTF tests
            13. Check Controller and Contrail nodes status

Actual result:
Such ostf tests failed on step 12:
AssertionError: Failed 7 OSTF tests; should fail 0 tests. Names of failed tests: [
 {
  "Request list of networks (failure)": "Networks list is unavailable. Please refer to OpenStack logs for more details."
 },
 {
  "Check network connectivity from instance via floating IP (failure)": "Time limit exceeded while waiting for security group creation to finish. Please refer to OpenStack logs for more details."
 },
 {
  "Create security group (failure)": "Time limit exceeded while waiting for security group creation to finish. Please refer to OpenStack logs for more details."
 },
 {
  "Check network parameters (failure)": "List of networks is not available. Please refer to OpenStack logs for more details."
 },
 {
  "Launch instance (failure)": "Time limit exceeded while waiting for security group creation to finish. Please refer to OpenStack logs for more details."
 },
 {
  "Launch instance with file injection (failure)": "Time limit exceeded while waiting for security group creation to finish. Please refer to OpenStack logs for more details."
 },
 {
  "Launch instance, create snapshot, launch instance from snapshot (failure)": "Image can not be booted. Please refer to OpenStack logs for more details."
 }