When a datatype is missing from the configuration we don't terminate properly

[joesiltberg]

To reproduce:

1. Create a self-sync with a complete set of configuration files (our standard LDAP example for instance).
2. Run the transfer
3. Change configuration to a configuration without for instance SchoolUnitGroup (our standard CSV example for instance).
4. Run again, with the missing type included in the send order to trigger the error
5. The client will print an error because we have a type in the send order which doesn't have a configuration file.
6. Fix the send order
7. Run again and notice that the SCIM server complains about removing objects that it doesn't know

The last point is probably because we deleted the objects in step 4, but this wasn't recorded in the cache file due to the program being terminated.

[joesiltberg]

See also #157