Moved Cinder QOS tests to admin directory

Cinder QOS API is admin by default[1][2]. This patch moves the
existing Cinder/Volume QOS tests to the volume/admin directory.

[1] http://developer.openstack.org/api-ref-blockstorage-v2.html
[2] http://git.openstack.org/cgit/openstack/cinder/tree/etc/cinder/policy.json#n32

Change-Id: Ic48cdea75b3393cfd4a856cd4adf171f3a002dff
diff --git a/tempest/api/volume/test_qos.py b/tempest/api/volume/admin/test_qos.py
similarity index 100%
rename from tempest/api/volume/test_qos.py
rename to tempest/api/volume/admin/test_qos.py