Fix: Reraise SecurityGroupLimitExceeded

- limit error was being swallowed causing a more esoteric error to be dumped later

Squashed commit of the following:

commit 507530469c2acd90c96a18ebdfbc7614721d788a
Author: David Snyder <david@infochimps.com>
Date:   Mon Apr 7 12:09:19 2014 -0500

    Don't swallow SecurityGroupLimitExceeded

    Change-Id: If9525c67c958d39886a805d9ff265821a413c114

Change-Id: I64c5f73a3a2c597f90a5dd44c14bcffb196c7836