SBI/PB registration with invalid workflow.

[bmort]

Describe the bug
Registering a processing block whose workflow has not been defined still results in a SBI in the configuration database with no PBs attached. This seems to be because the PB is rejected when the workflow is undefined but at that point the SBI has already been added to the DB.

To Reproduce
List steps to reproduce the behavior:
1a. Configure a SBI using the Tango Master Controller containing a PB with a workflow which is not currently registered.
1b. (not tested) use the CLI method skasip_config_db_add_sbi with a SBI with a PB where the workflow has not been registered
3. An error is reported but the SBI is entered into the DB.

Expected behavior
A clear error message should be reported and nothing should be entered into the DB so that the SBI can resubmitted.

Context
This was found running the SIP november 2018 demos.

[bmort]

Will be fixed in the update/workflow_definition branch.

[bmort]

This is now fixed in the update/workflow_definiton branch. As this branch introduces additional breaking changes however, it can not yet be merged into master. This should be resolved before SDP closeout at the end of March 19.