Clean up error logs.

Use %v for errors, tidy some messages, make error messages start lowe-case
(as per go guidelines).  Just accumulated nits.

pkg/api/validation/validation_test.go

@@ -805,7 +805,7 @@ func TestValidateService(t *testing.T) {
 		registry.List = tc.existing
 		errs := ValidateService(&tc.svc, registry, api.NewDefaultContext())
 		if len(errs) != tc.numErrs {
-			t.Errorf("Unexpected error list for case %q: %+v", tc.name, errs)
+			t.Errorf("Unexpected error list for case %q: %v", tc.name, errs.ToError())
 		}
 	}