test: fix cleanup sequence for test_acl_listvolume test
test: fix cleanup sequence for test_acl_listvolume test

Changes the cleanup sequence as the cleanup code causes exceptions in
several Travis runs such as:
https://travis-ci.org/apache/cloudstack/jobs/129925224

Signed-off-by: Rohit Yadav <902b9eb5dd62819678163bd5e00fbf0cbc7c264b@shapeblue.com>

wido/cloudstack,wido/cloudstack,DaanHoogland/cloudstack,GabrielBrascher/cloudstack,DaanHoogland/cloudstack,resmo/cloudstack,DaanHoogland/cloudstack,wido/cloudstack,resmo/cloudstack,GabrielBrascher/cloudstack,wido/cloudstack,DaanHoogland/cloudstack,resmo/cloudstack,jcshen007/cloudstack,jcshen007/cloudstack,jcshen007/cloudstack,GabrielBrascher/cloudstack,GabrielBrascher/cloudstack,resmo/cloudstack,jcshen007/cloudstack,GabrielBrascher/cloudstack,jcshen007/cloudstack,GabrielBrascher/cloudstack,DaanHoogland/cloudstack,wido/cloudstack,DaanHoogland/cloudstack,resmo/cloudstack,DaanHoogland/cloudstack,wido/cloudstack,jcshen007/cloudstack,resmo/cloudstack,GabrielBrascher/cloudstack,resmo/cloudstack,jcshen007/cloudstack,wido/cloudstack