Remove nova-manage image from man pages
Remove nova-manage image from man pages

There is no 'nova-manage image' subcommand so this removes
it's reference from the man pages.

Change-Id: Ia918006d58c8d7536c37187c37b8004c6f7d3aac
Closes-Bug: #1656686

phenoxim/nova,jianghuaw/nova,Juniper/nova,gooddata/openstack-nova,klmitch/nova,vmturbo/nova,Juniper/nova,gooddata/openstack-nova,vmturbo/nova,openstack/nova,jianghuaw/nova,rahulunair/nova,jianghuaw/nova,jianghuaw/nova,mikalstill/nova,klmitch/nova,Juniper/nova,gooddata/openstack-nova,rahulunair/nova,mikalstill/nova,mahak/nova,klmitch/nova,mahak/nova,vmturbo/nova,rahulunair/nova,openstack/nova,rajalokan/nova,vmturbo/nova,mikalstill/nova,gooddata/openstack-nova,klmitch/nova,openstack/nova,mahak/nova,Juniper/nova,rajalokan/nova,rajalokan/nova,rajalokan/nova,phenoxim/nova