Added missing argument to get_config()

This function was modified upstream by this commit
08f8773b  Yassine Lamgarchal2013-06-10 Add inst_type parameter
Signed-off-by: Tomoe Sugihara <tomoe@midokura.com>
Fix no name exception in oslo.config.StrOpt

Signed-off-by: Tomoe Sugihara <tomoe@midokura.com>
Merge pull request #48 from midokura/rossella/havana

Rossella/havana