[NaCl SDK] Cleanup dlopen tutorial.

Remove uneeded callback function from the worker thread.
Remove extra newlines between log message.

R=binji@chromium.org

Review URL: https://codereview.chromium.org/54543009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232502 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232502