Fix misused assertTrue in unit tests
Fix misused assertTrue in unit tests

Refactored unit tests to use assertEqual instead of assertTrue
where needed.

Closes-Bug: #1226374

Change-Id: I5f3b582e19f3461a04b5df05960095779ec8aa1a

ntt-sic/python-glanceclient,openstack/python-glanceclient,ntt-sic/python-glanceclient,alexpilotti/python-glanceclient,mmasaki/python-glanceclient,klmitch/python-glanceclient,mmasaki/python-glanceclient,openstack/python-glanceclient,alexpilotti/python-glanceclient,JioCloud/python-glanceclient,metacloud/python-glanceclient,JioCloud/python-glanceclient,metacloud/python-glanceclient,varunarya10/python-glanceclient,varunarya10/python-glanceclient,klmitch/python-glanceclient