Adding python test for ".." deletes

Appropriately fails with a ValidationException:
"Path contains illegal components"
Fix '%' string issue in OMERO5.0DEV

This fails with:
```
$ omero db script
Please enter omero.db.version [OMERO5.0DEV]:
Please enter omero.db.patch [1]:
Please enter password for OMERO root user:
Please re-enter password for OMERO root user:
Saving to /Users/mark/src/openmicroscopy/OMERO5.0DEV__1.sql
Error printing text
Failed to map line:                     RAISE EXCEPTION '%',
'Directory('||OLD.id||''||OLD.path||OLD.name||'/ is not empty!';')'
```
since the whole script is run through a Python  The functions
were appropriate for pasting directly into psql, but not for
`bin/omero db script`.