Prevent dvips from cluttering in the error log

Setup

You need a moodle install with the tex filter configured, that is easier said that done:

1. Disable the mathjax filter
2. Install latex, dvips and convert libraries sudo apt-get install texlive-full
3. Login as admin
4. Enable tex filter (Settings -> Site administration -> Plugins -> Filters -> Manage filters)
5. Click settings (next to tex filter) and make sure libraries point to right path
6. Create a label in course paste:

   $$ \sqrt {x + y}

   $$

7. Save and return to course
8. Make sure you can see square-root x + y image.
9. Inspect the image and make sure thats coming from filter/tex/pix.php and not mathjax

If you don't get to that point, you've likely got your install misconfigured..

Test
The test involves tailing your apache error log and make sure your not getting 'non-errors' about dvips in there, this is just one example of how to do it:

1. Ensure you've not got any pre-built tex by running rm -r moodledata/filter/tex/ and purging caches
2. Open new incognito window (eliminate browser cache)
3. Go to an atto editor and open the equation editor
4. VERIFY: that the apache error log is not spammed with many informational messags about dvips