This patch moves the glanceclient unit tests to the standard directory
(xxxclient/tests/unit) in preparation for adding functional gate tests
'check-glanceclient-dsvm-functional' in the same vein as existing client
tests for other projects, eg:
* check-novaclient-dsvm-functional
* check-keystoneclient-dsvm-functional
* check-neutronclient-dsvm-functional
Change-Id: I29d4b9e3a428c851575ee9afde40d6df583456c4