Bug 1069811 - AWS Linux Slave failed with failed to purge builds - Error: unable to free 20.00 GB of space. r=bhearsum

* Bump requred space for builder slaves up to 20G
Merging from default

changeset:   2285:504e0ec41685
tag:         tip
parent:      2283:b3537935f103
user:        Rail Aliiev <rail@mozilla.com>
date:        Mon Sep 22 09:16:45 2014 -0400
summary:     Bug 1069811 - AWS Linux Slave failed with failed to purge builds - Error: unable to free 20.00 GB of space. r=bhearsum

--HG--
branch : production