linting cleanup in kojibuild.py - F841
linting cleanup in kojibuild.py - F841

F841 local variable assigned to but never used

added one NOQA guard for action with sideffect
dropped one local assignment
added TODO comment about using a return value

Change-Id: I68e0207a42cf997ced1993206b1ef62783630e71

openstack-packages/rdopkg,redhat-openstack/rdopkg,redhat-openstack/rdopkg,openstack-packages/rdopkg