test_tasker: silence stickler-ci lint error
test_tasker: silence stickler-ci lint error

Fixes "F841 local variable '_' is assigned to but never used", by simply
removing the assignment, as suggested by Luiz.

Signed-off-by: Jarod Wilson <14059c7158912dcae849c377925c87d46da48cdf@redhat.com>

jarodwilson/atomic-reactor,projectatomic/atomic-reactor,DBuildService/atomic-reactor,projectatomic/atomic-reactor,maxamillion/atomic-reactor,jarodwilson/atomic-reactor,vrutkovs/atomic-reactor,vrutkovs/atomic-reactor,maxamillion/atomic-reactor,fr34k8/atomic-reactor,fr34k8/atomic-reactor,DBuildService/atomic-reactor