Fixes ambiguous cli output between "None" and NoneType
Fixes ambiguous cli output between "None" and NoneType

Print hyphen(-) in python client output when attribute value is not
set(NoneType) so that it is distinguishable between "None" string
and NoneType value.

Change-Id: I5ec0f39f13aca45fa95ddb59472c20207c63bf91
Closes-Bug: #1266414

CCI-MOC/python-novaclient,akash1808/python-novaclient,CCI-MOC/python-novaclient,JioCloud/python-novaclient,takeshineshiro/python-novaclient,guptaankita/python-novaclient,guptaankita/python-novaclient,JioCloud/python-novaclient,akash1808/python-novaclient,Shihta/python-novaclient,metacloud/python-novaclient,metacloud/python-novaclient,takeshineshiro/python-novaclient,Shihta/python-novaclient,mat128/python-novaclient,mat128/python-novaclient