Migrate manage script needs import of db session module
Migrate manage script needs import of db session module

This import looks like it is not used but importing this module as
the side effect of defining the olso configuration. Without it the
script will not work.

Change-Id: Id65f726f34aa2fb86fda13fd65e2e512b3a899ac

nikesh-mahalka/cinder,scality/cinder,spring-week-topos/cinder-week,abusse/cinder,Akrog/cinder,mahak/cinder,abusse/cinder,blueboxgroup/cinder,phenoxim/cinder,CloudServer/cinder,sasukeh/cinder,duhzecca/cinder,blueboxgroup/cinder,Thingee/cinder,ge0rgi/cinder,manojhirway/ExistingImagesOnNFS,JioCloud/cinder,openstack/cinder,NetApp/cinder,redhat-openstack/cinder,dims/cinder,Paul-Ezell/cinder-1,Paul-Ezell/cinder-1,sasukeh/cinder,bswartz/cinder,rakeshmi/cinder,saeki-masaki/cinder,duhzecca/cinder,alex8866/cinder,tlakshman26/cinder-bug-fix-volume-conversion-full,saeki-masaki/cinder,ntt-sic/cinder,rickerc/cinder_audit,JioCloud/cinder,petrutlucian94/cinder,tlakshman26/cinder-new-branch,openstack/cinder,Accelerite/cinder,Hybrid-Cloud/cinder,spring-week-topos/cinder-week,rickerc/cinder_audit,Akrog/cinder,nexusriot/cinder,tlakshman26/cinder-new-branch,cloudbase/cinder,apporc/cinder,Thingee/cinder,tlakshman26/cinder-bug-fix-volume-conversion-full,cloudbau/cinder,tlakshman26/cinder-https-changes,takeshineshiro/cinder,rakeshmi/cinder,NeCTAR-RC/cinder,CloudServer/cinder,eharney/cinder,Accelerite/cinder,julianwang/cinder,Thingee/cinder,petrutlucian94/cinder,github-borat/cinder,scality/cinder,mahak/cinder,redhat-openstack/cinder,eharney/cinder,dims/cinder,bswartz/cinder,NetApp/cinder,potsmaster/cinder,julianwang/cinder,j-griffith/cinder,winndows/cinder,alex8866/cinder,nikesh-mahalka/cinder,cloudbase/cinder,Nexenta/cinder,ntt-sic/cinder,NeCTAR-RC/cinder,nexusriot/cinder,Datera/cinder,Hybrid-Cloud/cinder,tlakshman26/cinder-https-changes,Nexenta/cinder,hguemar/cinder,takeshineshiro/cinder,phenoxim/cinder,Datera/cinder,apporc/cinder,manojhirway/ExistingImagesOnNFS,hguemar/cinder,leilihh/cinder,cloudbau/cinder,j-griffith/cinder,scottdangelo/RemoveVolumeMangerLocks,scottdangelo/RemoveVolumeMangerLocks,github-borat/cinder,potsmaster/cinder,winndows/cinder,leilihh/cinder