remove unused and buggy function from baremetal proxy
remove unused and buggy function from baremetal proxy

* nova/virt/baremetal/proxy.py (_fetch_image): This function
reference 'images' which is undefined.  So just remove it
as it's unused.

Change-Id: I7016f6e8a68fefab4342adadd032e93f963a074e

SauloAislan/ironic,faizan-barmawer/elytics,ionutbalutoiu/ironic,naterh/ironic,froyobin/ironic,naototty/vagrant-lxc-ironic,ramineni/myironic,openstack/ironic-lib,bacaldwell/ironic,redhat-openstack/ironic,faizan-barmawer/openstack_ironic,NaohiroTamura/ironic-lib,supermari0/ironic,varunarya10/ironic,openstack/ironic,dims/ironic,pshchelo/ironic,citrix-openstack-build/ironic-lib,hpproliant/ironic,citrix-openstack-build/ironic,JioCloud/ironic,citrix-openstack-build/ironic,NaohiroTamura/ironic,dims/ironic,rackerlabs/ironic,bacaldwell/ironic,emonty/ironic,SauloAislan/ironic,NaohiroTamura/ironic,ionutbalutoiu/ironic,faizan-barmawer/ironic-lib,devananda/ironic,Tehsmash/ironic,Tan0/ironic,debayanray/ironic_backup,openstack/ironic,naototty/vagrant-lxc-ironic,pshchelo/ironic,rdo-management/ironic