Fix volumes to use the supplied context
Fix volumes to use the supplied context

If the task specifies api_versions context at present, it doesn't get used
in context setup and defaults to hard-coded value from osclients.py, this
fix will pass the config to osclient which constructs correct versioned
client

Change-Id: I67766c3943f20aee8bd61ed76c04e79652f9b91a

vganapath/rally,eonpatapon/rally,yeming233/rally,gluke77/rally,gluke77/rally,amit0701/rally,eayunstack/rally,gluke77/rally,eonpatapon/rally,openstack/rally,vganapath/rally,openstack/rally,openstack/rally,gluke77/rally,vganapath/rally,openstack/rally,amit0701/rally,amit0701/rally,yeming233/rally,eayunstack/rally,eayunstack/rally,vganapath/rally