Relax prettytable dependency to v0.6.X from v0.6
Relax prettytable dependency to v0.6.X from v0.6

Change-Id: Ide7247ba444b60179d9c76c43dfaa43c025b69c9

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