Fix mistake in UT:test_detach_unattached_volume
Fix mistake in UT:test_detach_unattached_volume

Simple fix: volume's attach_status shoud not be 'in-use',
it should be 'attached' or 'detached'.

Change-Id: Ie0fedecbea04675bb26c071aa4cb4e6d248e6e24
Closes-Bug: #1486791

rahulunair/nova,apporc/nova,cloudbase/nova,JianyuWang/nova,ted-gould/nova,edulramirez/nova,vmturbo/nova,vmturbo/nova,mikalstill/nova,sebrandon1/nova,mikalstill/nova,edulramirez/nova,Juniper/nova,CEG-FYP-OpenStack/scheduler,BeyondTheClouds/nova,fnordahl/nova,ted-gould/nova,felixma/nova,cloudbase/nova,openstack/nova,mahak/nova,phenoxim/nova,cloudbase/nova,vmturbo/nova,Francis-Liu/animated-broccoli,BeyondTheClouds/nova,jianghuaw/nova,rahulunair/nova,gooddata/openstack-nova,jianghuaw/nova,cyx1231st/nova,zhimin711/nova,CEG-FYP-OpenStack/scheduler,klmitch/nova,devendermishrajio/nova,bigswitch/nova,fnordahl/nova,sebrandon1/nova,openstack/nova,Juniper/nova,MountainWei/nova,mahak/nova,rajalokan/nova,TwinkleChawla/nova,klmitch/nova,klmitch/nova,NeCTAR-RC/nova,zhimin711/nova,alaski/nova,alaski/nova,dims/nova,BeyondTheClouds/nova,cernops/nova,hanlind/nova,gooddata/openstack-nova,scripnichenko/nova,mahak/nova,cyx1231st/nova,Juniper/nova,felixma/nova,hanlind/nova,gooddata/openstack-nova,apporc/nova,CCI-MOC/nova,rajalokan/nova,CCI-MOC/nova,j-carpentier/nova,JianyuWang/nova,rahulunair/nova,MountainWei/nova,hanlind/nova,yosshy/nova,TwinkleChawla/nova,bigswitch/nova,openstack/nova,rajalokan/nova,Francis-Liu/animated-broccoli,mikalstill/nova,sebrandon1/nova,phenoxim/nova,raildo/nova,noironetworks/nova,devendermishrajio/nova,Juniper/nova,raildo/nova,vmturbo/nova,gooddata/openstack-nova,cernops/nova,scripnichenko/nova,j-carpentier/nova,NeCTAR-RC/nova,jianghuaw/nova,noironetworks/nova,klmitch/nova,dims/nova,jianghuaw/nova,yosshy/nova,rajalokan/nova,cernops/nova