Use single meta when change column type

Function _change_deleted_column_type_to_boolean_sqlite() from module
openstack.common.db.sqlalchemy.utils uses get_table() function to get
required Table object. Function get_table() creates a MetaData object and
returns the Table instance using this metadata. When function
`_change_deleted_column_type_to_boolean_sqlite` creates new table, it
also create new MetaData() objects.
It's works fine in most cases, but when table has foreign key, there is
no possibility to find related table for new table because related table
absent in new metadata.

To fix this issue we get metadata from received Table object.
Test added.

Fixes bug 1210163

Change-Id: I9c441d263e6e87fce702b12f5d2c4a9144cfb7e4
Merge "Use single meta when change column type"