Allow passing columns_to_join to instance_get_all_by_host_and_node()

This allows us to specify which columns should be loaded during this get
call. It is needed for the next patch which adds support for extra items
in the expected_attrs lists.

Change-Id: Id7d8fae9b0d3c7cf1f0f7debbe5d851696759c2c
Merge "Allow passing columns_to_join to instance_get_all_by_host_and_node()"