InfoS uses %#s for errors instead of %q

[serathius]

/kind bug
When working on kubernetes/kubernetes#91591 we noticed that

klog.V(2).InfoS("NODE DENY", "err", err)

was serialized to

I0603 09:57:29.759232   53238 node_authorizer.go:209] "NODE DENY" err=&errors.errorString{s:"node \"node2\" cannot get secret ns1/node1-only, no relationship to this object was found in the node authorizer graph"}

instead of

I0603 09:57:29.759232   53238 node_authorizer.go:209] "NODE DENY" err="node \"node2\" cannot get secret ns1/node1-only, no relationship to this object was found in the node authorizer graph"

Possibly it was fixed by #156
If so we should add tests for Error objects.

[tahsinrahman]

/assign