Do no depends on argparse for Python >= 2.7
Do no depends on argparse for Python >= 2.7

Python >= 2.7 has argparse has a builtin module, so there's no need to add
it to the this list of requirements.

Change-Id: I647cec70a564b1d184f0cb2aca6caf4d6478c403
Signed-off-by: Julien Danjou <02b9c1d548d177421b793c726ed68b7aac9b5a66@enovance.com>

ntt-sic/python-novaclient,JioCloud/python-novaclient,CCI-MOC/python-novaclient,metacloud/python-novaclient,mat128/python-novaclient,guptaankita/python-novaclient,CCI-MOC/python-novaclient,takeshineshiro/python-novaclient,akash1808/python-novaclient,metacloud/python-novaclient,Shihta/python-novaclient,ntt-sic/python-novaclient,JioCloud/python-novaclient,citrix-openstack-build/python-novaclient,takeshineshiro/python-novaclient,mat128/python-novaclient,guptaankita/python-novaclient,Shihta/python-novaclient,akash1808/python-novaclient,citrix-openstack-build/python-novaclient