Legacy MySQL datastore is shown on datastore-list

  On the 019_datastore_fix.py migration script the upgrade method was
calling the has_instances_wo_datastore_version as a function pointer
instead of passing the instance_table in and calling the function. This
meant the if block was always true because it was just checking if the
function exists and the create_legacy_version method was called everytime
causing the "Legacy MySQL" datastore to be inserted even if there was no
legacy trove instances. Now inject the instace_table into the
has_instances_wo_datastore_version and everything works as expected.

  Updated the datastore integration tests to not rely on the Legacy MySQL
datastore to exist by using the 10000000-0000-0000-0000-000000000001 GUID.
Instead the test now asserts against the data_store by the name
"Test_Datastore_1" which is the datastore the integration test
intended to validate against.

Closes-Bug: 1396427
Change-Id: Ifff33a962cc8d6ea150f6408d63b81412e196939