1. Fix lint errors for the whole directory staging/src/k8s.io/client-go/tools/cache;

2. Remove staging/src/k8s.io/client-go/tools/cache from .golint_failures;
3. Fix some typo from comments.

Kubernetes-commit: 0e0e1f7daba0a6ae6dd59df0a1bb643c323ad8cb

tools/cache/expiration_cache_test.go

@@ -181,7 +181,7 @@ func TestTTLPolicy(t *testing.T) {
 		t.Errorf("TTL Cache should expire entries older than ttl")
 	}
 	for _, ttl = range []time.Duration{0, -1} {
-		policy.Ttl = ttl
+		policy.TTL = ttl
 		if policy.IsExpired(fakeTimestampedEntry) {
 			t.Errorf("TTL policy should only expire entries when initialized with a ttl > 0")
 		}