integration: use %s for check.Commentf()

It is wrong to pass an arbitrary string to a function expecting
%-style formatting. One solution would be to replace any % with %%,
but it's easier to just do what this patch does.

Generated with:

for f in $(git grep -l 'check.Commentf(out)'); do \
	sed -i -e 's/check\.Commentf(out)/check.Commentf("%s", out)/g' $f; \
done

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

integration-cli/docker_cli_logout_test.go

@@ -59,7 +59,7 @@ func (s *DockerRegistryAuthHtpasswdSuite) TestLogoutWithExternalAuth(c *check.C)
 
 	// check I cannot pull anymore
 	out, err := s.d.Cmd("--config", tmp, "pull", repoName)
-	c.Assert(err, check.NotNil, check.Commentf(out))
+	c.Assert(err, check.NotNil, check.Commentf("%s", out))
 	c.Assert(out, checker.Contains, "no basic auth credentials")
 }