check-tempest-dsvm-ironic-pxe_ssh failed: cannot create directory '/opt/stack/new/.cache': Permission denied

[Dmitry Guryanov]

https://review.openstack.org/#/c/143471/1

Patchset 4 in review, check-tempest-dsvm-ironic-pxe_ssh failed, the error is in devstacklog.txt.gz:
http://logs.openstack.org/71/143471/4/check/check-tempest-dsvm-ironic-pxe_ssh/91e2175/logs/devstacklog.txt.gz

...
2014-12-25 14:27:43.422 | ++ local IRONIC_DEPLOY_KERNEL_PATH=/opt/stack/new/devstack/files/ir-deploy-pxe_ssh.kernel
2014-12-25 14:27:43.422 | ++ local IRONIC_DEPLOY_RAMDISK_PATH=/opt/stack/new/devstack/files/ir-deploy-pxe_ssh.initramfs
2014-12-25 14:27:43.422 | ++ '[' '!' -e /opt/stack/new/devstack/files/ir-deploy-pxe_ssh.initramfs -o '!' -e /opt/stack/new/devstack/files/ir-deploy-pxe_ssh.kernel ']'
2014-12-25 14:27:43.422 | ++ '[' True = True ']'
2014-12-25 14:27:43.422 | ++ '[' False '!=' True ']'
2014-12-25 14:27:43.422 | ++ is_deployed_by_agent
2014-12-25 14:27:43.422 | ++ [[ -z pxe_ssh ]]
2014-12-25 14:27:43.422 | ++ return 1
2014-12-25 14:27:43.422 | ++ ramdisk-image-create ubuntu deploy-ironic -o /opt/stack/new/devstack/files/ir-deploy-pxe_ssh
2014-12-25 14:27:43.432 | mkdir: cannot create directory '/opt/stack/new/.cache': Permission denied

2014-12-25 14:27:43.432 | + exit_trap
2014-12-25 14:27:43.432 | + local r=1
2014-12-25 14:27:43.433 | ++ jobs -p
2014-12-25 14:27:43.434 | + jobs='24813
2014-12-25 14:27:43.434 | 4580'
2014-12-25 14:27:43.434 | + [[ -n 24813
2014-12-25 14:27:43.434 | 4580 ]]
....