Demote error.log messages "Deadline exceeded for rewrite" from 'error' to 'info'

[GoogleCodeExporter]

Since installing the latest version, I notice in my logfiles, that I keep 
seeing the error:

[mod_pagespeed 0.10.21.2-1381 @31237] Deadline exceeded for rewrite of resource 
http://www.sellmyretro.com/themes/enuukGreen/img/box1.png with ic

Oddly it only seems to affect three images:
http://www.sellmyretro.com/themes/enuukGreen/img/box1.png
http://www.sellmyretro.com/themes/enuukGreen/img/box2.png
http://www.sellmyretro.com/themes/enuukGreen/img/box3.png

They are not large images and I cannot see why modpagespeed is struggling...

Original issue reported on code.google.com by rwap.services on 18 Feb 2012 at 8:35