Use sqlite3.backup
The next version 3.7 (normally) of Python should support backup in sqlite3.
So we could stop using sqlitebck for the test.
https://github.com/python/cpython/commit/d7aed4102d2a40c74553240c7f03585624d27aea
The next version 3.7 (normally) of Python should support backup in sqlite3.
So we could stop using sqlitebck for the test.
https://github.com/python/cpython/commit/d7aed4102d2a40c74553240c7f03585624d27aea