[devtools/qunit] Remove unused code VerboseCalledProcessError is unused since 3905682ece11.

[py3k] import range using six.moves Also, use create_entity instead of hand-crafting RQL queries. Fixes regression introduced in commit 768d332de17b.

[dataimport] remove size constraint handling We do not want to silently truncate data. If that is wanted, the application-specific importer should handle that itself. [v2: Keep the get_size_constraints function so applications don't have to reimplement it if they need to keep the truncate behaviour]